AMER. ZOOL., 13:775-792 (1973).
Endocrine Control of Calcium Metabolism in Teleosts
PETER K. T. PANG
Department of Pharmacology, College of Physicians and Surgeons of
Columbia University, New York, New York 10032
SYNOPSIS. It is evident that fishes regulate their serum calcium efficiently but that
endocrine systems involved may be different from those in tetrapods. A functional
parathyroid gland has not yet been demonstrated in fishes. The majority of evidence
indicates that calcitonin has little or no effect on fish calcium regulation. Instead, the
corpuscles of Stannius and the pituitary gland are necessary for maintaining fish serum
calcium levels. In the killifish, Fundulus heteroclitus, the removal of the corpuscles
produces hypercalcemia in sea water but not in artificial sea water deficient in calcium.
Transplants of the corpuscles or the administration of corpuscle homogenate corrects
the increase in calcium. On the other hand, hypophysectomy elicits hypocalcemia
under calcium deficient conditions but not in calcium rich sea water. Replacement
therapy with pituitary homogenate or hypophysial transplant prevents the fall in
calcium. It is postulated that the hypocalcemic corpuscles of Stannius and the hypercalcemic pituitary gland enable the euryhaline killifish to regulate its serum calcium
levels in high calcium sea water and low calcium fresh water, respectively.
and Forster, 1972). I believe that the aquatic
environment renders fish calcium metabolThe calcium metabolism of fishes is par- ism unique among vertebrates and different
ticularly interesting because of their aquatic from that of the terrestrial tetrapods. Alenvironment. In sea water or hard, fresh though some tetrapods have an aquatic
water, the environmental calcium level may habitat, most breathe air and have less exbe four or more times that of the fish's body changeable surface area in contact with the
fluid while the calcium level in soft fresh surrounding medium than fishes which rewater may be one tenth that of fish blood. spire through the gills.
Fresh water fishes face the constant danger
The main features of tetrapod calcium
of calcium loss. Therefore, there must be metabolism are, essentially, the absorption
very efficient systems for preventing this of calcium from food, the prevention of
loss and for obtaining calcium from the en- calcium loss from the body and the ability
vironment. Since the opposite problem ex- to mobilize calcium in case of need. To
ists in sea water, marine or euryhaline fishes deal with the last problem, tetrapods rely
must be able to actively excrete the calcium heavily on their calcium storage, the bony
entering from external sources and to limit tissues. In fishes, the problems of getting rid
its rate of entrance. Regardless of the mech- of excess calcium in sea water or obtaining
anisms actually employed, euryhaline fishes enough calcium in fresh water are continusuch as eels and killifish are able to maintain ous challenges which are closely related to
their serum calcium levels quite precisely in the external medium.
both fresh and sea water (Chan and Chester
In tetrapods, the delicate balance of calJones, 1968; Pickford et al., 1969; Fenwick cium is under the control of parathyroid
hormone and, probably, calcitonin. DisturbThe unpublished work described in this review
was supported by NIH Grant AM 01940 and NSF ances in calcium metabolism are often reflected in serum calcium levels. Thus, paraGrant GB-30598X to Dr. W. H. Sawyer. I am
grateful to Dr. Sawyer for reading the manuscript. thyroidectomy results in extreme hypocalI also thank Dr. D. H. Copp for the salmon calci- cemia and, at times, tetanic seizures, while
tonin, Dr. J. W. Bastian (Armour Pharmaceutical
Company) for the porcine calcitonin, Dr. A. S. injections of parathyroid hormone correct
Ridolfo (Lilly Laboratory) for the parathyroid ex- these changes. On the other hand, in some
tract, and NIH for the prolactin.
mammals injection of calcitonin produces
INTRODUCTION
775
776
PETER K. T. PANG
hypocalcemia and in some amphibians the
removal of the calcitonin source results in
an abnormal calcium balance (Robertson,
1970). It seems that parathyroid hormone
promotes calcium absorption from the digestive tract and calcium resorption from
bone and prevents urinary calcium loss. Calcitonin reduces calcium resorption from
storage reservoirs. Probably, it is by the
delicate balance of these two systems that
precise regulation of calcium metabolism is
achieved in tetrapods.
Fishes, the most abundant and diversified
group of vertebrates, are, as indicated previously, able to regulate their calcium levels.
However, their hormonal regulation of this
electrolyte is poorly understood and the literature is contradictory and confusing. In
recent years, the relation between calcium
metabolism and various endocrine systems
in fishes has been studied more extensively.
However, several problems still remain unsolved. Firstly, it is not known whether a
functional parathyroid gland is present.
Secondly, whether calcitonin plays a role in
fish calcium metabolism is highly controversial. Thirdly, the nature of the calcium
regulating endocrine system has not been
demonstrated.
PARATHYROID GLAND
The parathyroid gland has generally been
considered absent in fishes (Fleischman,
1947; Hoar, 1951; Pickford, 1953). However,
Rasquin and Rosenbloom (1954) suggested
that the ultimobranchial gland might have
functions analogous to those of the parathyi-oicl gland in this vertebrate group.
These authors, studying the effects of complete darkness on the Mexican characin,
Astyanax mexicanus, reported skeletal deformation and hypertrophy of the ultimobranchial gland. They concluded that the
overactivity of the ultimobranchial body
caused excessive skeletal resorption. However, in Funduhis heteroclitus, disturbances
in calcium metabolism of fish kept in complete darkness were corrected by the administration of vitamin C (Pang, 1971b). In
addition, the ultimobranchial gland of various species has been established as a rich
source of calcitonin (Copp et al., 1967;
Copp etal., 1968; Pang et al., 1971a). Therefore, it is very unlikely that the ultimobranchial body represents the parathyroid gland
in fishes.
Nevertheless, it is still possible that a
functional parathyroid gland is present and
awaits discovery. If this is true, one should
be able to demonstrate the effects of parathyroid hormone. Mammalian parathyroid
preparations, shown to be effective in nonmammalian tetrapods, have frequently been
tested on fishes.
Injections of mammalian parathyroid extracts had no consistent hypercalcemic effect
on various teleostean fishes (Fleming and
Meier, 1960, 1961o>; Clark and Fleming,
1963; Moss, 1963; Oguri and Takada, 1966;
Fleming, 1967) and were ineffective in inducing scale growth, resorption, or regeneration (Yamada, 1961) or in changing bone
and muscle mineral content (Rampone,
cited by Hoar, 1957). Budde (1958) demonstrated an osteological response by Lcbistcs
reticulatits to parathyroid extract injections
but subsequent investigations in other species of fish failed to show similar changes
(Clark and Fleming, 1963; Moss, 1963). MeFarland (1968) reported that parathyroid
tissues had no effect on fish bone resorption
in vitro.
In the lizard, Anolis carolinensis, injections of parathyroid extract given to intact
animals had no statistically significant effect
on serum calcium levels. However, when the
hormone was injected into parathyroidectomized animals, the hypercalcemic effects
of the hormone became evident in these hypocalcemic and tetanic lizards (Clark et al.,
1969). Since the experiments on parathyroid
hormone administration were performed on
intact fishes, the negative findings cannot be
viewed as conclusive evidence for the absence of responsiveness to parathyroid hormone. Hypocalcemia and tetanic seizures
have recently been successfully induced in
the killifish, F. heteroclitus (Pang et al.,
19716). This provided an ideal system for
testing the hypercalcemic effects of parathyroid hormone. In three separate experiments the same parathyroid extract that was
effective in correcting hypocalcemia in para-
CALCIUM METABOLISM IN TELEOSTS
TABLE 1. Effects of mammalian parathyroid extract
on serum calcium Irvclx of male F. heteroelitus
adapted to calcium deficient sea icater.
Serum Ca:* (msi/1)
Experiment
1) 5 daily injections
Control -+- saline
Fluoride treated -f- saline
Fluoride treated + PTH
2) 1 injection
Hypects. •+• saline
Hj-pects. -f- PTH
3) 5 daily injections
Hypects. -f- saline
Hypects. + PTH
2.95 ± 0.10 (10)*
2.53 ± 0.12 (10)**
2.38 ±0.10 ( 1 1 ) "
1.79 ± 0.22 (4)
1.95 ± 0.18 (4)
1.94 ± 0.12 (5)
2.04 ± 0.19 (5)
* Data are given as mean ± SB (no. of fish).
** Significantly different from the controls (Student's t test) ; P < 0.05.
(Pajig, unpublished.)
thyroidectomized lizards failed to alleviate
the hypocalcemia and tetanic seizures of hypophysectomized or sodium fluoride treated
F. heteroelitus (Table 1) (Pang, unpublished). Thus, these experiments fail to support the hypothesis that fishes have a functional parathyroid gland. But they do not
rule it out. Therefore, further studies are
needed.
CALCITONIN
The discovery of calcitonin as a possible
hypocalcemic hormone in mammals (Copp
et al., 1962; Hirsch et al., 1964) led to hopeful expectations that this hormone might be
important in fish calcium metabolism. Investigations concerning the administration
of this hormone to fishes were reviewed by
Pang (1971c). In that review, the initial findings by Pang and Pickford (1967) that mammalian calcitonin failed to elicit hypocalcemia in the killifish, F. heteroelitus, were
confirmed by subsequent experiments. The
absence of effects of mammalian and salmon
calcitonins was also shown in other species
of fish (catfish and coho salmon). Louw et
al. (1967) reported hypocalcemia in catfish
treated with a crude mammalian calcitonin
preparation. However, these findings have
recently been questioned (Kenny, 1972).
The hypocalcemic influence of crude mammalian calcitonin preparations or the ultimobranchial body was suggested by work
777
with European and Japanese eels, Anguilla
(inguilla and A. japonica, respectively (Chan
et al., 1968ft; Chan, 1970). Subsequent investigators failed to confirm the hypocalcemic effects of this hormone in either European or American eels (Hayslett et al., 1971;
Dacke, cited by Kenny, 1972). Recently,
Orimo et al (1971) isolated calcitonin from
Japanese eels and failed to demonstrate a
consistent hypocalcemic effect of this purified hormone on A. japonica. In the trout,
Salmo gairdneri, maintained in deionized
water and treated with thyroxine, hypocalcemia and bone demineralization were evident. Treatment of such fish with calcitonin
prevented the bone demineralization but
had no effect on the decrease in serum calcium levels (Lopez et al., 1971). Copp et al.
(1972) studied the effects of salmon calcitonin on blood and urine calcium metabolism in salmon and failed to observe any
effect.
Pang (1971c) suggested that calcitonin
might be related to osmoregulation. Eel calcitonin has since been shown to decrease
serum osmolality, sodium, and chloride in
Japanese eels (Orimo et al., 1971, 1972). In
a series of experiments with F. heteroelitus,
chronic injections of either mammalian or
salmon calcitonin appeared to have a hypochloremic effect. However, this effect was
evident only in fish receiving fourteen or
more injections of calcitonin (Table 2). In
one experiment, 21 injections of salmon calcitonin also produced hypercalcemia. Since
the experiments were conducted with intact
fish, it was suspected that the endogenous
calcitonin might exert maximal effects already. The ultimobranchial body, which is
the source of calcitonin in fishes, may be
under pituitary control (Pang, 1971c). If
this is true, the effects of chronic injections
of calcitonin would become more pronounced if the fish are hypophysectomized
beforehand to reduce the endogenous calcitonin. A pilot experiment with hypophysectomized killifish showed that four injections of calcitonin did indeed produce hypochloremia (Table 3).
Dacke et al. (1971) reported an increase in
plasma calcitonin levels in fishes injected
with a calcium chloride solution. Deftos et
778
PETER K. T. PANG
TABLE 2. Effects of chronic injections of calcitonin on serum electrolyte levels of intact male
F. heteroclitus.
Cl- (mM/1)
Experiment
A) Fish adapted to sea water
1) 2 daily injections
Saline
Calcitonin
2) 4 daily injections
Saline
Calcitonin
3) 8 daily injections
Saline
Calcitonin
4) 21 daily injections
Saline
Calcitonin
B) Fish adapted to calcium
deficient sea water
1) 4 daily inj ections
Saline
Calcitonin
2) 14 daily injections
Saline
Calcitonin
3) 15 daily injections
Saline
Calcitonin
160.1 ± 1.8 (7)
155.8 ± 1.4 (7)
141.5 ± 2.7 (7)
142.5 ± 2.4 (7)
2.76 ± 0.11 (7)
2.73 ± 0.13 (4)
174.8 ± 2.9 (7)
165.5 ± 2.8 (6)
147.2 ± 4.3 (7)
136.8 ± 5.1 (6)
2.14 ± 0.15 (6)
2.27 ± 0.19 (6)
169.8 ± 1.8 (6)
166.1 ± 1.8 (6)
129.3 ± 3.1 (6)
123.7 ± 3.2 (6)
2.47 ± 0.08 (8)
2.91 ± 0.11 (8)**
141.9 ± 1.1 (7)
131.6 ± 2.3 (8)**
2.62 ± 0.20 (9)
2.38 ± 0.07 (9)
186.1 ±14.9 (6)
163.9 ± 5.5 (9)
2.55 ± 0.13 (4)
2.27 ± 0.09 (4)
173.0 ± 5.3 (9)
175.0 ± 2.0 (10)
166.9 ±15.0 (6)
136.1 ± 4.0 (8)**
154.2 ± 6.0 (7)
135.5 ± 3.8 (5)**
2.65 ± 0.05 (7)
2.84 ± 0.13 (6)
See Table 1. (Pang and Pang, unpublished.)
al. (1972) also described an increase in
plasma calcitonin levels in salmon when calcium chloride was added to the surrounding
medium. In addition, a fall in circulating
hormone was seen in fishes which migrated
from sea to fresh water. Nevertheless, the
physiological effect of calcitonin on fish calcium metabolism remains obscure.
The above discussion indicates that parathyroid hormone and calcitonin, which
probably are the two most important endocrine principles in mammalian calcium
metabolism, may have little importance in
fish calcium regulation. On the other hand,
fishes are capable of regulating their serum
calcium rather precisely regardless of the
calcium challenges they face in their natural
habitat. It is, therefore, logical to assume the
existence of some other efficient endocrine
control. Several endocrine systems were
studied in relation to killifish calcium metabolism (Pang, 1970). Of all the systems
investigated, two have profound effects on
calcium metabolism. They are discussed be-
low with reference to the existing literature.
CORPUSCLES OF STANNIUS
The first system to be discussed is the
corpuscles of Stannius. Fontaine (1964) demonstrated that the surgical removal of this
tissue from European eels produced hypercalcemia. Pang (1971a) reviewed subsequent
similar findings by various investigators
working with European, Japanese, and
American eels and goldfish, and reported
the hypercalcemic effect of stanniectomy on
the killifish, F. heteroclitus. Subsequent unTABLE 3. Effects of chronic injections of calcitonin
on serum chloride levels of hypophysectoviized male
F. heteroclitus adapted to sea water.
Experiment
4 daily injections
Saline
Calcitonin
Cl- (mM/1)
158.4 ± 9.3 (5)
133.9 ± 4 . 7 ( 6 ) "
See Table 1.
(Pang and Pang, unpublished.)
CALCIUM METABOLISM IN TELEOSTS
TABLE 4. Effects of stanniectomy on serum calcium
levels of female F. heteroclitus kept in one-third
sea water and fed regular calcium rich food.
Experiment
1) 5 days after operation
Operated controls
Stanniects.
2) 8 days after operation
Operated controls
Stanniects.
3) 14 days after operation
Operated controls
Stanniects.
Ca=t (msi/1)
3.63 ± 0.37 (5)
4.93 ± 0.45 ( 7 ) "
2.76 ± 0.24 (5)
5.47 ±0.57 (9)**
2.30 ± 0.12 (7)
3.20 ± 0.16 (5)»*
See Table 1.
(Pang, unpublished.)
published studies confirmed these findings
(Table 4). Therefore, it seems that this
gland is important in fish calcium metabolism. However, stanniectomy also elicits
changes in other serum electrolytes. It thus
becomes important to determine whether
the effect on the serum calcium level is specifically related to calcium metabolism or
merely a reflection of disturbances in the
regulation of other electrolytes or in osmoregulation. Histological examination of
this gland in high and low calcium environments should answer this question. When
previous investigators conducted histological studies of this gland taken from fish
adapted to sea water, which is high in calcium, and to fresh water, which is low in
calcium, results indicated that the glands
are more active in sea water than in fresh
water (Olivereau, 1964; Fontaine and Lopez,
1965; Hanke et al., 1967; Johnson, 1972).
This, of course, supports the hypothesis that
the corpuscles of Stannius promote hypocalcemia and are directly concerned with calcium metabolism. However, these findings
are not decisive since the levels of electrolytes other than calcium, and the osmotic
pressure, of fresh water and sea water are
very different.
Recently, Miss Rochelle Cohen of the Department of Life Sciences, University of
Connecticut and I studied the effects of calcium deprivation on the ultrastructure of
the corpuscles of Stannius of fish adapted to
sea water. Killifish were maintained for four
or more weeks in regular sea water or arti-
779
ficial calcium deficient sea water. The calcium levels of these two media were about
40 and 2 mg %, respectively. It is obvious
that there is a high calcium challenge in sea
water which is reversed in calcium deficient
sea water. This may be reflected in the calcium levels of the fish (Pang et al., 19716).
Since the stanniectomy experiments showed
that these glands have hypocalcemic effects,
they should be more active in sea water than
they are in calcium deficient sea water. Electron microscopic studies indicate that this
is true. The glands from fish in sea water
exhibited a high degree of synthetic and
secretory activities as indicated by rough
endoplasmic reticulum, hyperactive Golgi
apparatus, granular depletion, and the presence of lysosome-like bodies. Such indications of activity were not obvious in the
glands from fish maintained in calcium deficient sea water. These findings are described in a preliminary report (Cohen et
al., 1972). Since the only difference between
the two groups of fish was the difference in
environmental calcium levels, the difference
in glandular activities should be due to calcium and calcium alone.
That the corpuscles of Stannius affect
calcium metabolism in the teleost fish
studied is quite obvious. However, very
little is known about the nature of the secretion or the mechanism of action of this
gland. It was suggested that the rise in serum
calcium after stanniectomy reflected a decrease in urinary calcium loss and that the
effect on urine loss could be corrected by
infusion of corpuscles of Stannius homogenate or homotransplantation of the tissues
(Chan et al., 1969). However, Butler (1969),
working with the American eel, Anguilla
rostrata, failed to detect a decrease in urinary calcium excretion after the removal of
the corpuscles of Stannius and suggested
bone as a possible target organ. On the
other hand, Lopez (1970) described a decrease in bone resorption after stanniectomy
in the European eel. It therefore becomes
very important to study kidney function in
killifish in relation to the action of the corpuscles of Stannius.
I believe that the main function of the
corpuscles of Stannius. is to maintain serum
780
PETER K. T. PANG
introduction, the relationship of the fish to
the aquatic environment makes the problems of calcium regulation in fishes different
from those of the terrestrial vetebrates. Such
problems are, perhaps, solved with endocrine systems different from those of the
tetrapods.
The chemical nature of the secretion of
the corpuscles of Stannius remains a subject
of controversy. Fontaine and Leloup-Hatty
(1959), Cedard and Fontaine (1963), Ozon,
Fontaine and Cedard (cited by Breuer and
Ozon, 1965), Idler and Freeman (1966),
Krishnamurthy (1968), and Colombo et al.
(1971) claimed to have demonstrated the
occurrence or the in vitro synthesis of adrenocorticosteroids in this tissue. However,
other investigators failed to do so (Ford,
1959; Phillips and Mulrow, 1959; Roy, 1964;
Chester [ones and Henderson, 1965; Chester
Jones et al., 1965; Sandor et al., 1966; Arai
et al., 1969). The enzymes essential for steroidogenesis are also reported to be absent
from this gland (Chieffi and Botte, 1963«,6;
Botte etal., 1964; Bara, 1968; Nadkarni and
Lapinsky, 1968). From their electron microscopic studies, Oguri (1966), Ogawa (1967),
and Tomasulo (1968) observed that the
secretion of the gland is proteinaceous in
nature. Similar observations were made on
the killifish (Cohen and Pang, unpublished).
Although a renin-like substance was demonstrated in fish corpuscles of Stannius (Chester (ones and Henderson, 1965; Chester
Jones et al., 1966; Sokabe, 1968; Sokabe et
al., 1968), they contain relatively little renin
compared to the kidney (Sokabe et al., 1970).
The physiological importance of renin and
TABLE 5. Effects of stanniectomy on serum calcium angiotensin in the corpuscles would then
levels of male F. lieteroelitus kept in one-third calcium deficient .sea water and fed low calcium food. require further investigation.
Fontaine (1964) reported that injections
Experiment
Ca" (niM/1)
of corpuscles of Stannius extract restored
1) 5 days after operation
the serum electrolyte levels of stanniectoOperated controls
2.60 ± 0.10 (5)
mized eels to normal. Homotransplants of
Stanniects.
2.49 ± 0.13 (6)
the glands have similar corrective effects on
2) 7 days after operation
eels (Fenwick and Forster, 1972). In killifish,
2.28 ± 0.10 (6)
Operated controls
both treatments are effective (see Table 6).
2.19 ± 0.07 (6)
Stanniects.
calcium levels in high calcium environments, while their role in low calcium environments is minimal. However, previous
investigators reported hypercalcemia in
stanniectomized fish maintained in fresh
water (Fontaine, 1964, 1967; Chester Jones
and Henderson, 1965; Chester Jones et al.,
1967; Rankin et al., 1967; Chan et al., 1969;
Chan, 1970). In some studies where stanniectomy was performed on both freshwater- and seawater-adapted eels, the hypercalcemic response was much greater in
seawater-adapted eels than in those adapted to fresh water (Fenwick and Forster,
1972). Fenwick and Forster also showed
that hypercalcemia appeared only at 2
weeks after stanniectomy of freshwater eels,
while a marked response was seen in seawater eels as early as 10 days after the operation. It is also possible that the fresh
water in some of these studies may contain
appreciable amounts of calcium.
Recent studies on killifish (Pang, unpublished) revealed that the magnitude of the
hypercalcemic response to stanniectomy increases with an increase in the environmental calcium challenge. In fish adapted to
calcium deficient sea water, a hypercalcemic
response was totally absent from the operated animals (Table 5). These studies confirm the hypothesis that the corpuscles of
Stannius have a hypocalcemic function in
fishes facing a high environmental calcium
challenge and that their role in low calcium
media is minimal. This information would
also define the importance of environmental
calcium metabolism. As pointed out in the
3) 14 days after operation
Operated controls
Staiuiiectb.
Si'e Table 1.
(Pang, unpublished.)
2.33 ± 0.12 (6)
2.08 ± 0.0G (8)
PITUITARY GLAND
The other endocrine organ that has a
prolound effect on fish calcium metabolism
CALCIUM METABOLISM IN TELF.OSTS
TABLE 6. Effects of replacement therapy on serum
calcium levels of stanniectomized male F. heteroelitus Tccpt in sea icater and fed regular calcium
rich food for two weelcs.
Groups
Ca=
1) Operated controls
2) Stanniects.
3) Staimiects. + 14 injections of
Staiuiius corpuscles homogonate
4) Staimiects. -f Staiuiius corpuscles transplants
3.57 ± 0.08 (8)*
4.90 ± 0.39 (9)
3.46 ± 0.08 (9)*
3.90 ± 0.17 (8)*
See Table 1.
* Significantly different from the Stajiniects.
(Student's t test) ; P < 0.001.
(Pang, unpublished.)
is the pituitary gland. Many investigators
have looked into this problem previously.
It was pointed out in an earlier publication
(Pang et al., 1971) that other investigators
failed to establish a distinct relationship
between the pituitary gland and fish calcium metabolism. However, our findings in
that report show that the pituitary gland
regulates calcium metabolism in the killifish, F. heteroclitus, adapted to a low calcium environment. When the pituitary
gland was removed surgically from fish
adapted to artificial sea water deficient in
calcium, the experimental animals exhibited extreme hypocalcemia and tetanic seizures. This was the first time that tetany was
induced and correlated with hypocalcemia
infishes.A decrease in serum calcium levels
after hypophysectomy has been observed in
eels adapted to fresh water (Fontaine, 1956;
Olivereau and Chartier-Baraduc, 1965; Chan
and Chester Jones, 1968; Chan et al., 1968«).
However, in those experiments, hypophysectomy also produced hyponatremia and disturbances in osmoregulation. Chan and
Chester Jones (1968) believed that the hypocalcemia in the hypophysectomized eels
might simply reflect osmoregulatory problems. Since our tetanic fish were maintained
in sea water that was only deficient in calcium, no consistent osmotic difficulties were
evident, and we therefore suggested that the
observed hypocalcemia represented a real
defect in calcium metabolism as a result of
the removal of the pituitary gland. A subsequent experiment with another species of
the genus Fundulus, F. diaphanus, adapted
781
to fresh water supported this hypothesis
(Pangetal., 1973«).
To substantiate our claim that the pituitary gland has a physiologically hypercalcemic function, replacement therapy was
given to hypocalcemic killifish that had
been hypophysectomized and maintained in
calcium-deficient sea water. In one experiment, either a whole pituitary homogenate
was injected daily for 5 days into the experimental fish or the pituitary gland was
transplanted under the skin on the side of
the body. The transplants survived well. In
both cases, normal calcium levels were
maintained. Hypophysectomized fish injected with liver homogenate were hypocalcemic. The results are summarized in
Table 7. These findings strongly support
our hypothesis that the pituitary gland contains a factor or factors essential for the
maintenance of serum calcium levels in fish
inhabiting environments low in calcium.
What is the hypercalcemic hormone (or
hormones) in the pituitary gland? To look
into this, two approaches have been taken.
An attempt has been made to divide the
killifish pituitary gland into three different
regions, the anterior, median, and posterior
parts. Five hundred glands have been divided in such a manner, and homogenates of
each part were made. Previous histological
studies of killifish pituitary glands showed
that the anterior part contains mainly prolactin cells bordered by ACTH cells. The
median part is composed of cells producing
TSH, STH, and gonadothrophins. The posterior part is equivalent to the pars intermedia of higher vertebrates. The neurophypophysis interdigitates abundantly with
the median and posterior regions. It was
hoped that replacement therapy with homogenates of the three different parts might
reveal the location of the hypercalcemic
factor or factors. The results of the experiment are shown in Table 7.
Although the homogenates from all three
parts were effective in raising serum calcium
levels of the hypocalcemic fish, that from
the median part was the least effective.
Since the three parts were only very roughly
divided, contamination of the median part
with tissues from the other two parts was
782
PETER K. T. PANG
inevitable. This would easily explain the
significant corrective effect of the homogenate of the median part. Since the anterior
and posterior parts were equally effective,
it was suspected that during the collection
of tissues, there might inadvertently have
been some interchanging of the two parts.
On the other hand, it is known that the
molecular structure of mammalian MSH
and ACTH are very similar. It is then
possible that the ACTH from the anterior
part and the MSH from the posterior part
mimic each other at high dosage levels. It
is evident from the over-correction of the
serum calcium levels that the dose of the
TABLE 7. Effects of replacement therapy on serum
calcium levels of hypophysectomized male F. heteroclitus adapted to calcium deficient sea water
and fed low calcium food.
Groups
Ca2* (mM/1)
1)
2)
3)
4)
2.68
2.08
1.94
2.47
5)
6)
7)
8)
Operated controls
Hypeets.
Hypeets. + liverhomogenate
Hypeets. + whole pituitary
homogenate
Hypeets. + homogenate of
anterior part of pituitary
gland
Hypeets. + homogenate of
middle part of pituitary
gland
Hypeets. + homogenate of
posterior part of pituitary gland
Hypeets. + pituitary
transplant
±
±
±
±
0.14 (5)
0.09 (5)**
0.12 (8)**
0.11 (10)
2.73 ± 0.21 (9)
2.49 ± 0.21 (9)
2.88 ± 0.20 (9)
2.43 ± 0.11 (10)
See Table 1.
(Pang et al., 19736.)
injection was too high. The serum calcium
levels of fish receiving homogenates from
these two parts of the pituitary gland were
higher than the mock operated controls.
To pursue this further, ACTH or mammalian MSH was given to the hypocalcemic fish in another experiment. In addition, cortisol and ovine prolactin were
also tested, since ACTH should stimulate
cortisol release, and prolactin should be
abundant in the homogenate of the anterior part of the pituitary gland. The results are summarized in Table 8.
It is interesting to note that although
ACTH, cortisol, and prolactin were all
effective in correcting the hypocalcemia,
MSH was ineffective. The experiment was
TABLE 8. Effects of pituitary hormones on serum
calcium levels of hypophysectomized male F. heteroclitus adapted to calcium deficient sea water
and fed low calcium food. (Experiment 1.)
Groups
Ca 2
1)
2)
3)
4)
5)
6)
2.36 ±
1.75 ±
2.18 ±
2.50 ±
2.49 ±
1.97 ±
Operated controls + saline
Hypeets. + saline
Hypeets. + cortisol, 2.5 A g/g
Hypects. + ACTH, 0.05 IU/g
Hypeets. + prolactin, 5 ^g/g
Hypeets. + MSH, 2.5 /jg/g
0.15 (5)*
0.13 (5)
0.06 (10)*
0.27 (10)*
0.14 (5)*
0.O8 (10)
See Table 1.
* Significantly different from group 2 (Student's
t test) ; P < 0.05.
(Pang et al., 19736.)
subsequently repeated with lower doses of
ACTH and prolactin and a higher dose
of MSH. In that experiment, the lower
doses of ACTH and the high dose of MSH
had no effect while prolactin, even at the
lowest dose, one-tenth of that used in the
previous experiment, was effective (Table 9).
The evidence collected to date is far from
conclusive, but it does suggest that prolactin, and probably also ACTH, are involved
in the regulation of serum calcium levels of
killifish maintained in a low calcium environment (Pang et al., 19736). The hypercalcemic effect of prolactin has been observed in eels (Olivereau and Olivereau,
1970). It is possible that ACTH and prolactin act together in hypercalcemic regulation. The synergistic effect of these two
hormones on calcium regulation has been
demonstrated in eels (Chan et al., 1968a).
The participation of prolactin in hypercalcemic regulation fits the current views on
TABLE 9. Effects of pituitary hormones on serum
calcium levels of male F . heteroclitus adapted to
calcium deficient sea water and fed low calcium
food. (Experiment
2.)
Groups
Caa+
1) Operated controls + saline
2) Hypeets. -f saline
3) Hypeets. + AOTH,
0.02 IU/g
4) Hypects. + ACTH,
0.005 IU/g
5) Hypeets. -+- prolactin,
2/Jg/g
6) Hypects. + prolaetin,
05 j g /g
7) Hypects.+1ISH.
2.87 ±0.08 (9)»
2.25 ± 0.06 (10)
2.34 ± 0.06 (10)
See Table 8.
(Pang et al., 19736.)
2.23 ± 0.05 (9)
2.58 ± 0.57 (8)*
2.64 ±0.05 (10)"
2.16 ± 0.07 (7)
CALCIUM METABOLISM IN TELEOSTS
the physiological function of this hormone
in fishes. It has been well established that
prolactin is important in osmoregulation in
the freshwater fishes. In nature, the only
low calcium environment that a fish would
encounter is fresh water. That the hormone
for osmoregulation also regulates calcium
would then be understandable. At present
these are simply speculations and many
more experiments are required to clarify
the identity of the calcium regulating hormone from the pituitary gland.
We should note that the hypercalcemic
function of the pituitary gland is important
only in environments that are low in calcium. If the fish are hypophysectomized in
sea water which is rich in calcium, no
change in serum calcium levels would be
seen. Also, the hypocalcemia in hypophysectomized fish maintained in calcium deficient
sea water can be corrected by returning the
fish to regular sea water (Pang et al., 19716).
Obviously, then, the hormone or hormones
would be secreted when the fish are maintained in a low calcium environment.
Therefore, histological studies of this gland
in high and low calcium sea water would
help us identify the hormone or hormones
in the pituitary gland. Such studies are in
progress and the results will become available in the near future.
OTHER ENDOCRINE ORGANS
Other endocrine organs, including the
gonads, and the thyroid, interrenal, and
pineal glands, have been implicated in fish
calcium metabolism. These studies will not
be discussed in detail. Instead, pertinent
literature will be tabulated for the convenience of the reader and some important
features and contradictions will be discussed
in the text. It is be lieved that apart from
the ovaries these systems contribute little
to fish calcium metabolism.
Gonads
Table 10 summarizes the reported studies
on the gonads and calcium metabolism.
These studies clearly indicate that female
fish have higher serum calcium levels during ovarian maturation, probably due to
783
increased estrogen secretion. The administration of estradiol increases fish serum calcium levels. This increase is associated with
a rise in protein bound calcium and not in
ionic calcium (Bailey, 1957a; Chan and Chester Jones, 1968; Urist and Sehjeide, 1961).
It is believed that the protein is incorporated into the yolk and stored for future
embryonic development.
Most studies on male fish failed to show
a distinct relation between testicular maturation and serum calcium levels (see table
10). However, a significant decrease in serum
calcium levels was observed in male Salmo
salar spawning in fresh water (van Someren,
1937; Fontaine et al., 1969). On the other
hand, hypercalcemia occurred in mature
male Gadus morhna in sea water (Woodhead and Woodhead, 1964; Woodhead,
1968; Woodhead and Plack, 1968). Since
fresh water is low in calcium and sea water
is high in this ion, it is possible that these
two species failed to regulate their calcium
in relation to the environmental challenge
during sexual maturation. The most logical
approach to this problem is to observe the
effects of male sex hormones on fish calcium
levels. Testosterone propionate did not affect serum calcium levels in male goldfish
(Bailey, 1957a), but Peterson and Shehadeh
(1971), citing the data from one fish, claimed
that methyltestosterone increased serum calcium in a male mullet (Mugil cephalus).
Administration of crude fish gonadotropins
induced testicular hydration in male goldfish, but serum calcium was not changed
(Grant et al., 1969). Many reports show that
female sex hormones have a hypercalcemic
effect on male fish (see Table 10), but unless
a high level of the female sex hormone is
demonstrated in reproductively active male
fishes, hypercalcemic effects of estrogen on
these organisms have little or no meaning
in the context of their normal physiology.
Male killifish reproduce annually in the
laboratory even under constant periods of
light and dark and constant temperature
(Pickford, unpublished). When serum calcium levels in killifish are measured in association with testicular maturation, no
correlation is seen between these levels and
testicular size (Fig. 1). In the same figure,
the serum calcium levels are given for cas-
Carass-ins auraius
C. auraius
Tilapia csculcnta
Bailey (3957a)
Bailey (1957b)
Garrod and Newell (1958)
(cited by Woodhead, 1968)
Sano (1960)
Fleming and Meier (1961a)
Fontaine et al. (1964)
Woodhead and Woodhead (1964)
ORiiri and Takada (1966)
Chan and Chester Jones (1968)
Woodhead (1968)
Woodhead and Plack (1968)
Fontaine et al. (1969)
Stanley (1969)
Woodhead (1969a)
Woodhead (1969ft)
Peterson and Sheliaded (1971)
Booke (1964)
Fleming et al. (1964)
Ho and Vanstone (1961)
Trist and Schjcide (1961)
Clark and Fleming (1963)
Sdltno salar
van SomeiTii (1937)
Anguilla anguilla
Gadits morhua
Cliana argus
A. anguilla
G. morhua
G. morhua
S. salar
Alosa psrudoharengus
Scyliorhinus canicnla
G. morhua
Mngil cephalus
F. Tcansae
Salvelinns fontinalis
F. Tcansae
Salmo gairdnerii
Fundulus Tcansae,
F. eatenatus
Oncorhynchns nerTca
Paralabrax claihratits
F. leansae
Cod and puffer
Species
Mii-sclier (1897)
Hcssetal. (1928)
Authors
Serum calcium levels were elevated during egg laying season.
Females had higher serum calcium levels than males. These could be correlated
with gonadal maturation.
Males maintained constant, serum calcium levels until just, before spa.wni.ng; females showed increase during maturation. At spawning, decrease seen, in
both sexes.
One injection of estradiol increased total and non-ultrafiltrable calcium levels
for 20 days. Testosterone propionate had no effect.
Same as above.
Females showed higher serum calcium levels when sexually mature; males did
not.
Claimed higher serum calcium levels in summer, but no sex differentiation.
Estradiol induced hypercalcemia in males and females.
Conclusions
Estradiol benzoato elevated serum calcium levels of both sexes.
Serum calcium in the form of calcium proreina.te was increased by estrone.
Estradiol increased serum total calcium. Histology and x-ray of bone showed
FW
no changes.
FW
Females had higher serum calcium levels during spawning; males did not.
Males showed no seasonal cycle in sorum calcium levels but females exhibited
salt
hypercalcemia. in summer.
spring
FW
Estradiol increased serum calcium level in females. Tho rise was greater if
there was calcium in the water.
FW
Females had higher serum calcium levels when sexually mature.
Hypercalcemia. coincided with gonadal maturation in both sexes.
SW
Estradiol elevated serum calcium levels but sexes of fish were not separated.
FW
Estrogen treatment increased total and non-ultrafiltrable calcium levels.
FW
Gonadal maturation raised plasma calcium levels in both sexes.
SW
Same as above.
SW
Both sexes showed decrease in serum ca.lcium levels during spawning.
FW
Claimed hypercalcemia in breeding males but not females.
FW
Estradiol benzoate increased plasma, total calcium in females.
SW
Estradiol benzoate increased plasma, calcium in both sexes.
SW
Methyltestosterone increased serum calcium level in an experiment with one
male mullet.
FW
FW
FW
FW
rw
FW
FW
SW
Medium
TABLE 10. Jiclationship betwien the gonads and calcium metabolism in fishes.
a
-A
ft
7a
CALCIUM METABOLISM IN TELEOSTS
III
785
2
if!
Ill;
s
.2
o
O
is'
'S
FIG. 1. Testicular activities and serum total calcium levels in killifish, F. heteroclitus, maintained
in sea water.
i 2 's 2 =
a v •
-SO
o ° °
ill
c~i
^
c; u —
§ c o
ts
.3 o o f,
CaoH — o
. a
Si
-js «
6
| ? 1 b yl& ."« "= ? "3 j? £
< «
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so
= .£ s
3
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8 ?
8 s
r S o
CO
-
o
f Jill
I
fiSStJK
o
o
trated males and operated controls (Pang,
unpublished). Again, no difference is seen.
These studies support the hypothesis that
calcium metabolism is not affected by testicular development. This is understandable
since, compared to the females, mobilization
of calcium into the gonads is much less
drastic in male fish.
Thyroid gland
Previous investigations of the thyroid
gland and fish calcium metabolism are summarized in Table 11. Most studies indicated
that thyroxine prevented estrogen induced
hypercalcemia. When rainbow trout were
immersed in a solution of thyroxine and
tri-idothyronine, hypocalcemia was observed
(Chartier-Baraduc, 1968). However, radiothyroidectomized trout had normal serum
calcium levels (La Roche et al., 1966). Ball
and Ensor (1967) reported hypercalcemia in
freshwater- or dilute seawater-adapted
Poecillia latipinna, injected with thyrotropin. This problem has been investigated
in male F. heteroclitus (Table 12) (Pang unpublished). In three separate experiments,
food containing thyroid powder produced
hypocalcemia. Ten injections of thyroxine
or three injections of TSH had a similar
effect. However, in other experiments, ten
or twenty injections of thyroxine or the
administration of thyroxine and tri-iodothyronine by injection or in the external
media had no significant effect. Such contra-
786
PETER K. T. PANG
TABLE 12. Effects of thyroid substances on serum calcium levels of male hillifish, F. heteroclitus.
Serum Ca2* (mM/1)
Experiment
Controls
Experimentals
1) Thyroid feeding, F.W.
2.72 -+- 0.12
(16)
2) Thyroid feeding, S.W.
2.28 •+• 0.10
3) Thyroxine (T4), 10 inj., F.W.
2.52 •+• 0.07
(8)
(8)
4) T4, 20 inj., F.W.
3.19 -t- 0.05
5) T4, 10 inj., hypect, S.W.
3.24 -+- 0.08
(10)
2.56 -i- 0.07
6) Thyroid feeding, F.W.
2.40 -t- 0.10
7) TSH, 3 inj., F.W.
2.70 •+• 0.07
(6)
(8)
8) T3 and T4, in F.W.
2.98 -4- 0.11
3.07 -*- 0.10
(8)
(8)
9) T3 andT4, 3 inj., F.W.
3.14-1- 0.13
3.21 -t- 0.06
(7)
(8)
(7)
(6)
(7)
2.37 -+- 0.13**
(16)
1.98 •+- 0.04**
(7)
2.28 -i- 0.09**
(H)
2.48 -t- 0.06
(9)
2.08 •+- 0.04**
(7)
2.38 -i- 0.09**
See Table 1.
(Pang, unpublished.)
dictions even within the same species o£ fish
makes it impossible to draw any conclusion
concerning the relation between thyroid
function and fish calcium metabolism. Probably, thyroid hormones possess a hypocalcemic effect, demonstrable only under some
special physiological conditions which have
yet to be identified.
Interrenal gland
In the section concerning the pituitary
gland, the possible participation of the
pituitary-interrenal axis in conjunction with
prolactin in the regulation of serum calcium
levels in low calcium environments was discussed. Literature on interrenal hormones
and fish calcium metabolism is presented in
Table 13, but no consistent picture can be
seen in all these studies. In a series of studies
on eels (Chan et al., 1967; Chan and Chester
Jones, 1968), it was reported that interrenalectomy caused a fall in plasma calcium
in freshwater silver eels and a rise in that
of sea water silver eels, but not in yellow
eels maintained in either media. Treatment
with cortisol, aldosterone, and adrenocorticotropin (ACTH) did not have consistent
effects either. Butler et al. (1969) detected
a decrease in plasma calcium in one of three
groups of interrenalectomized freshwater
eels. Fleming, et al., (1964) reported hypocalcemia in winter but not summer male
and female F. kansae held in deionized
water and treated with ACTH. In Channa
argus, a freshwater fish cortisol had no
effect on serum or urine calcium levels
(Oguri and Takada, 1966).
Injections of cortisol given to hypophysectomized male or female F. heteroclitus
in sea water had no effect on total or dialytic
calcium levels (Pickford et al., 1970). In
another experiment, treatment of seawateradapted male killifish with metopirone produced no significant effects on serum calcium levels (Table 14) (Pang, unpublished).
As discussed above in the section concerning
the pituitary gland, a synergistic effect of
prolactin and ACTH was suggested by Chan
et al. (1968a). Therefore, if the pituitaryinterrenal axis is involved in calcium metabolism, it would probably be for the maintenance of calcium levels in a low calcium
environment.
Pineal gland
Skeletal deformities have been demonstrated in pinealectomized guppies and
small salmon (Pflugfelder, 1953, 1967). Un-
787
CALCIUM METABOLISM IN TELEOSTS
fortunately, serum calcium levels were not
studied in those experiments. However, in
view of the skeletal changes, it was suspected
that the pineal gland might be involved in
fish calcium metabolism. Weisbart and Fenwick (1968) failed to show any change in
serum calcium levels in pinealectomized
goldfish maintained in fresh water. Similar
negative findings were obtained with F.
heteroclitus pinealectomized in sea water
(Table 15) (Pang, unpublished). Therefore;
a pineal effect on fish calcium regulation
seems rather unlikely.
3
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CONCLUSION
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1966)
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Our studies with F. heteroclitus, using to
date more than 2,500 fish, have been very
rewarding. These studies have shown us
that, at least in killifish, the endocrine control of calcium metabolism is very different
from that of tetrapods. Parathyroid hormone and calcitonin appear to have little
or no physiological significance in the calcium metabolism of this species of fish. Of
all the endocrine systems studied, the pituitary gland and the corpuscles of Stannius
are most consistently demonstrated to be involved; the former being hypercalcemic and
the latter hypocalcemic. It is necessary to
reiterate that the Stannius corpuscles are
important in environments high in calcium
but probably not in low calcium environments, and the opposite is true for the pituitary gland. The possession of these two systems enables a euryhaline fish like F. heteroclitus to regulate its calcium in sea water as
well as in fresh water. The adjustment of
their activities under different environmental calcium challenges helps the fish to
maintain a stable serum calcium level. As
discussed above, the fact that the corpuscles
of Stannius are dispensable in environments poor in calcium and the pituitary
gland in environments rich in calcium,
strongly supports my idea that these two
systems are physiologically meaningful and
that the exchange with the environment is
an integral part of calcium, metabolism in
killifish.
It is impossible to generalize for all fishes
from our data since killifish have acellular
3
6
6
M
788
PETER K. T. PANG
calcium levin of Bldlf killifish, F. hetero.
TABLE 14. Effects of meiopironr treatment on xerum
clitus, kepi in sea( water.
Totiil C :\r* (lllM/1)
Group
3.22 -+- 0..19 (5)
2.90 ± 0,.15 (5)
Controls
Metopirone treated
Di alytic Ca2* (niM/1)
0.71
0.73
H-
0.,12 (5)
± 0,,18(5)
See Table 1.
(Pang, unpublished.)
bone. It has been suggested that acellular
bone, in contrast to cellular bone, is physiologically dead and that its calcium cannot
be resorbed for regulation (Moss, 1962;
Simmons, 1971). Thus, the calcium metabolism of fishes with cellular bone may be different. Nevertheless, work with eels, a fish
TABLE 15. Effects of pinealeciomy on serum calcium levels of male, killifish, F. heteroelitus, kept
in sea water.
G roup
Mock-operated controls
Pinenlects.
calcium challenge. When tetrapods moved
onto land from the aquatic habitat, they
also left the continuous calcium challenge.
The importance of the bony tissues as calcium reservoirs then becomes evident and
with it, a different set of endocrine controls
for calcium metabolism comes into play
(Fig. 2). If this hypothesis is true, this would
be one of the important adjustments vertebrates made when they moved from water
to land during evolution.
Ca2+
2.82 ± 0.22 (8)
2.46 ± 0.32 (4)
See Table 1.
(Pang, unpublished.)
with cellular bone, has revealed the presence of hypercalcemia after stanniectomy
and hypocalcemia following hypophysectomy, and it is possible that fishes with
either cellular or acellular bone may have
similar endocrine regulation of calcium
metabolism.
It seems obvious that fishes regulate their
calcium in relation to the environmental
FIG. 2. Evolution of endocrine control of calcium
metabolism in vertebrates. B: bone; Ca: calcium;
C.S.: coipusclcs of Slannkis; CTX: calcitonin; F.W.:
fresh water; I: intestine; K: kidney; Pit.: pituitary
gland; 1'IH: paratlmoid hormone; S.W.: stu water.
REFERENCES
Arai, R., H. Tajima, and B. I. Tainaoki. 1969. In
vitro transformation of steroids by the head kidney, the body kidney and the corpuscles of Stannius of the rainbow trout. Gen. Comp. Entlocrinol.
12:99-109.
Bailey, R. E. 1957a. The effect of estradiol on serum
calcium, phosphorus and protein of goldfish. J.
Exp. Zool. 136:455-469.
Bailey, R. E. 1957b. Effect of thyroxine and estradiol
on the serum calcium, phosphorus and protein of
goldfish. Anat. Rec. 128:519-520.
Ball, J. N., and D. M. Ensor. 1967. Specific action of
prolactin on plasma sodium levels in hypophysectomized Poecilia latipinna (Teleostei). Gen. Comp.
Endocrinol. 8:432-440.
Bara, G. 1968. Histochemical study of 3/3 and 3a,
11/3 and 17/3 hydroxysteroid dehydrogenases in the
adrenocortical tissue and the corpuscles of Stannius of Fundulus heteroelitus. Gen. Comp. Endocrinol. 10:126-137.
Booke, H. E. 1964. Blood scrum protein and calcium
levels in yearling brook trout. Prog. Fish-Cult.
26:107-110.
Botte, V., C. Buonanno, and G. Chiefli. 1964. Osservazioni sulla istofisiologia deH'interrenale e dei
corpuscoli di Stannius di alcuni Teleostei. Boll.
Zool. 31:461-470.
Breuer, H., and R. Ozon. 1965. Metabolisme des
hormones steroides androgencs et oestrogenes chez
les vertebrates inferieurs. Arch. Anat. Microsc. 54:
17-33.
Budde, Sr. >f. L. 1958. The effects of parathyroid
extract upon the leleost fish Lebistes reticulatus.
Growth 22:73-91.
Butler, D. G. 1969. Corpuscles of Stannius and renal
physiology in the eel (Anguilla rostrata). J. Fish.
RLS. Board Can. 2fi:639-fu4.
CALCIUM METABOLISM IN TELEOSTS
Butler, D. G., W. C. Clarke, E. M. Donaldson, and
R. W. Langford. 1969. Surgical adrenalectomy of
a teleost fish (Anguilla rostrata Le Sueur): effect
on plasma cortisol and tissue electrolyte and carbohydrate concentrations. Gen. Comp. Endocrinol.
12:503-514.
C&lard, L., and M. Fontaine. 1963. Sur la presence
de steroides sexuels dans les corpuscles de Stannius du salmon atlantique {Salmo salar L.). C. R.
Hebd. Seances Acad. Sci. (Paris) 257:3095-3097.
Chan, D. K. O. 1970. Endocrine regulation o£ calcium and inorganic phosphate balance in freshwater adapted teleost fish, Anguilla anguilla and
A. japonica, p. 709-716. Proc. 3rd Int. Congr. Endocrinol. Excerpta Med. Int. Cong. Ser. No. 184.
Chan, D. K. O., and I. Chester Jones. 1968. Regulation and distribution of plasma calcium and inorganic phosphate in the European eel {Anguilla
anguilla L.). J. Endocrinol. 32:109-117.
Chan, D. K. O., I. Chester Jones, I. W. Henderson,
and J. C. Rankin. 1967. Studies on the experimental alterations of water and electrolyte composition
of the eel (Anguilla anguilla L.). J. Endocrinol.
37:297-317.
Chan, D. K. O., I. Chester Jones, and W. Mosley.
1968a. Pituitary and adrenocortical factors in the
control of the water and electrolyte composition
of the freshwater European eel {Anguilla anguilla
L.). J. Endocrinol. 42:91-98.
Chan, D. K. O., I. Chester Jones, and R. N. Smith.
19686. The effect of mammalian calcitonin on the
plasma levels of calcium and inorganic phosphate
in the European eel {Anguilla anguilla L.). Gen.
Comp. Endocrinol. 11:243-245.
Chan, D. K. O., J. C. Rankin, and I. Chester Jones.
1969. Influence of the adrenal cortex and the corpuscles of Stannius on osmoregulation in the European eel {Anguilla anguilla L.) adapted to fresh
water. Gen. Comp. Endocrinol. Suppl. 2:342-353.
Chartier-Baraduc, M. 1968. Effets de l'administration
prolongee d'hormones thyroidienne sur la composition hydromin£rale de quelques tissues de la
truite arc-en-ciel, Salmo gairdnerii. C. R. Seances
Soc. Biol. 162:640-644.
Chester Jones, I., D. K. O. Chan, E. W. Henderson,
W. Mosley, T. Sandor, G. P. Vinson, and A. B.
Whitehouse. 1965. Failure of corpuscles of Stannius of the European eel {Anguilla anguilla L.)
to produce corticosteroids in vitro. J. Endocrinol.
33:319-320.
Chester Jones, I., and I. W. Henderson. 1965. Electrolyte changes in the European eel {Anguilla
anguilla L.). J. Endocrinol. 32:iii-iv.
Chester Jones, I., I. W. Henderson, D. K. O. Chan,
and J. C. Rankin. 1967. Steroids and pressor substances in bony fish with special reference to the
adrenal cortex and corpuscles of Stannius of the
eel {Anguilla anguilla L.), p. 136-143. Proc. Int.
Congr. Steroid Hormones. Excerpta Med. Int.
Congr. Ser. No. 132.
Chester Jones, I., I. W. Henderson, D. K. O. Chan,
J. C. Rankin, W. Mosley, J. J. Brown, A. F. Lever,
J. I. S. Robertson, and M. Tree. 1966. Pressor ac-
789
tivity of extracts of the corpuscles of Stannius
from the European eel (Anguilla anguilla L.). J.
Endocrinol. 34:570-572.
Chieffi, G., and V. Botte. 1963a. Comportamento
istochimico
della
steroid-3-/9-ol-deidrogenasinell'interrenale e nei corpuscoli di Stannius de
Anguilla anguilla L. Atti. Acad. Naz. Lincei
Rend. 34:570-572.
Chieffi, G., and V. Botte. 1963&. Histochemical reaction for steroid-3-/9-ol-dehydrogenase in the interrenal and the corpuscles of Stannius of Anguilla
anguilla and Conger conger. Nature (London)
200:793-794.
Clark, N. B., and W. R. Fleming. 1963. The effect of
mammalian parathyroid hormone on bone histology and serum calcium levels in Fundulus kansae.
Gen. Comp. Endocrinol. 3:461-467.
Clark, N. B., P. K. T. Pang, and M. W. Dix. 1969.
Parathyroid glands and calcium and phosphate
regulation in the lizard, Anolis carolinensis. Gen.
Comp. Endocrinol. 12:614-618.
Cohen, R. S., N. B. Clark, and P. K. T. Pang. 1972.
Ultrastructure of the corpuscles of Stannius of the
killifish, Fundulus heteroclitus, and its relation
to calcium metabolism. Amer. Zool. 12:676.
(Abstr.)
Columbo, L., H. A. Bern, and J. Peiprzyk. 1971. Steroid transformations by the corpuscles of Stannius
and the body kidney of Salmo gairdnerii (Teleosteii). Gen. Comp. Endocrinol. 16:74-84.
Copp, D. H., P. G. H. Byfield, C. R. Kerr, F. Newsome, V. Walker, and E. G. Watts. 1972. Calcitonin and ultimobranchial functions in fishes and
birds, p. 12-20. In R. V. Talmage and P. L. Munson [ed.], Calcium, parathyroid hormone and the
calcitonins. Excerpta Medica, Amsterdam.
Copp, D. H., E. C. Cameron, B. A. Cheney, A. G. F.
Davidson, and K. G. Henze. 1962. Evidence for
calcitonin a new hormone from the parathyroid
that lowers blood calcium. Endocrinology 70:638649.
Copp, D. H., D. W. Cockroft, and Y. Kueh. 1967.
Calcitonin from ultimobranchial glands of dogfish and chickens. Science 158:924-925.
Copp, D. H., D. W. Cockroft, Y. Kueh, and M. Melville. 1968. Calcitonin-ultimobranchial hormone,
p. 306-321. In S. Taylor [ed.], Calcitonin. SpringerVerlag, Inc., New York.
Dacke, C. G., W. R. Fleming, and A. D. Kenny. 1971.
Plasma calcitonin levels in fish. Physiologist 14:
127.
Deftos, L. J., E. G. Watts, and D. H. Copp. 1972.
Sex differences in calcitonin (CT) secretion by
salmon, p. 180. IV. Int. Congr. Endocrinol. Int.
Congr. Ser. No. 256.
Etienne, N. 1958. Action des ions potassium, magnesium et calcium sur la fonction thyroidienne de
la truite arc-en-ciel (Salmo irideus gairdnerii).
C. R. Seances Soc. 3iol. 152:308-312.
Fenwick, J. C, and M. E. Forster. 1972. Effects of
Stanniectomy and hypophysectomy on total plasma
cortisol levels in the eel {Anguilla anguilla L.).
Gen. Comp. Endocrinol. 19:184-191.
790
PETER K. T. PANG
Fleischman, W. 1947. Comparative physiology of the
thyroid gland. Quart. Rev. Biol. 22:119-140.
Fleming, W. R. 1967. Calcium metabolism of teleosts. Amer. Zool. 7:835-842.
Fleming, W. R., and A. H. Meier, 1960. The effect
of mammalian parathormone on the serum calcium levels of Fundulus kansae and Fundulus
catenatus. Anat. Rec. 137:357.
Fleming, W. R., and A. H. Meier. 1961a. The effect
of mammalian parathormone on the serum calcium levels of Fundulus kansae and Fundulus
catenatus. Comp. Biochem. Physiol. 2:1-7.
Fleming, W. R., and A. H. Meier. 19616. Further
studies of the effect of mammalian parathyroid
extract on the serum calcium levels of two closely
related teleosts. Comp. Biochem. Physiol. 3:27-29.
Fleming, W. R., J. G. Stanley, and A. H. Meier.
1964. Seasonal effects of external calcium, estradiol, and ACTH on the serum calcium and sodium levels of Fundulus kansae. Gen. Comp.
Endocrinol. 4:61-67.
Fontaine, M. 1956.- The hormonal control of water
and salt-electrolyte metabolism in fish. Mem. Soc.
Endocrinol. 5:69-81.
Fontaine, M. 1964. Corpuscles de Stannius et regulation ionique (Ca, K, Na) du millieu interieur de
l'anguille (Anguilla anguilla L.). C. R. Hebd.
Seances Acad. Sci. (Paris) 259:875-878.
Fontaine, M. 1967. Intervention des corpuscles de
Stannius dans l'equilibre phosphocalcique du milieu interieur d'un poisson t£leost£en, l'anguille.
C. R. Hebd. Seances Acad. Sci. (Paris) 264:736737.
Fontaine, M., E. Bertrand, E. Lopez, and O. Callamand. 1964. Sur la maturation des organes genitaux de l'anguille femelle (Anguilla anguilla L.)
et remission spontanee des oeufs en aquarium.
C. R. Hebd. Seances Acad. Sci. (Paris) 259:29072910.
Fontaine, M., M. Chartier-Baraduc, J. Deville, E.
Lopez, and M. Poncet. 1969. Sur les variations de
la calcteiie observers chez Salmo salar L. a divers
e'tapes de son cycle vital. Leur d£terminisme endocrinien et leur intervention eVentuelle sur le
comportement. C. R. Hebd. Seances Acad. Sci.
(Paris) 268:1958-1961.
Fontaine, M., and J. LeLoup-Hatey. 1959. Corticosteroids in salmon corpuscles of Stannius. J.
Physiol. (Paris) 51:468-469.
Fontaine, M., and M. Lopez. 1965. Endocrine function of corpuscles of Stannius with special reference to the physiological preparation for catadromic migration of two migratory teleosts (Salmo
salar L. and Anguilla vulgaris L.). XXIII. Int.
Congr. Physiol. No. 244.
Ford, P. 1959. Some observations on the corpuscles
of Stannius, p. 159-168. In A. Gorbman fed.], Comparative endocrinology. John Wiley and Sons,
New York.
Grant, F. B., P. K. T. Pang, and R. W. Griffith.
1969. The twenty-four hour seminal hydration
response in goldfish (Carassius auratus). I. Sodium,
potassium, calcium, magnesium, chloride and os-
molality of serum and seminal fluid. Comp. Biochem. Physiol. 30:273-280.
Hanke, W., K. Bergerhoff, and D. K. O. Chan. 1967.
Histological observations on pituitary ACTHcells, adrenal cortex and the corpuscles of Stannius of the European eel (Anguilla anguilla L.).
Gen. Comp. Endocrinol. 9:64-75.
Hayslett, J. P., M. Epstein, D. Spector, J. D. Myers,
H. V. Murdaugh, and F. H. Epstein. 1971. Effect
of calcitonin on sodium metabolism in Squalus
acanthas and Anguilla rostrata. Bull. Mt. Desert
Is. Biol. Lab. 11:33-35.
Hess, A. F., C. E. Bills, M. Weinstock, and H. Rivkin. 1928. Differences in calcium level of the blood
between male and female cod. Proc. Soc. Exp.
Biol. Med. 25:349-350.
Hirsch, P. F., E. F. Voelkel, and P. L. Munson. 1964.
Thyrocalcitonin: hypocalcemic hypophosphatemic
principle of the thyroid gland. Science 146:412413.
Ho, F. C. W., and W. E. Vanstone. 1961. Effect of
estradiol monobenzoate on some serum constituents of maturing sockeye salmon (Oncorhynchus
nerka). J. Fish. Res. Board Can. 18:859-864.
Hoar, W. S. 1951. Hormones in fish, p. 1-51. In Some
aspects of the physiology of fish. Univ. of Toronto Biol. Ser. No. 59.
Hoar, W. S. 1957. The endocrine organs, p. 245277. In M. E. Brown [ed.], The physiology of
fishes. Academic Press, New York.
Idler, D. R., and K. C. Freeman. 1966. Steroid transformations by corpuscles of Stannius of the Atlantic cod (Gadus morhua L.). J. Fish. Res. Board
Can. 23:1249-1255.
Johnson, D. W. 1972. Variations in the interrenal
and corpuscles of Stannius of Mugil cephalus from
the Colorado River and its estuary. Gen. Comp.
Endocrinol. 19:7-25.
Kenny, A. D. 1972. Introductory remarks, p. 9-11.
R. V. Talmage and P. L. Munson [ed.], Calcium,
parathyroid hormone and the calcitonins. Excerpta Medica, Amsterdam.
Krishnamurthy, V. G. 1968. Histochemical and biochemical studies of the corpuscles of Stannius of
the teleost fish Colisa lalia. Gen. Comp. Endocrinol. 11:92-103.
La Roche, G., A. N. Woodall, C. L. Johnson, and
J. E. Halver. 1966. Thyroid function in the rainbow trout (Salmo gairderi Rich.): II. Effects of
thyroidectomy on the development of young fish.
Gen. Comp. Endocrinol. 6:249-266.
Lopez, E. 1970. L'os cellulaire d'un poisson teleosteen "Anguilla anguilla L." II. Action de l'ablation des corpuscles de Stannius. Z. Zellforsch. 109:
566-572.
Lopez, E., M. Chartier-Baraduc, and J. Deville.
1971. Mise en evidence de 1'action de la calcitonine porcine sur l'os de la truite Salmo gairdnerii
soumise a un traitement d£mineralisant. C. R.
Hebd. Seances Acad. Sci. (Paris) 272:2600-2603.
Louw, G. N., W. S. Sutton, and A. D. Kenny. 1967.
Action of thyrocalcitonin in the teleost fish Ictalurus melas. Nature (London) 215:888-889.
CALCIUM METABOLISM IN TELEOSTS
791
McFarland, A. 1968. An experimental study of the Pang, P. K. T., N. B. Clark, and K. S. Thomson.
1971a. Hypocalcemic activities in the ultimobransupposed parathyroid-like activity of the ultimochial bodies of lungfishes, Neoceratodus forsteri
branchial body of fish and of the species specificity
and Lepidosiren paradoxa and teleosts, Fundulus
of parathyroid action on bone. J. Anat. 102:578heteroclitus and Gadus morhua. Gen. Comp. En579.
docrinol. 17:582-585.
Miescher, F. 1897. Die histochemischen und physioPang, P. K. T., R. W. Griffith, and G. E. Pickford.
logischen Arbeiten. F. C. W. Vogel, Leipzig.
19716. Hypocalcemia and tetanic seizures in hypoMoss, M. L. 1962. Studies of acellular bone of teleost
physectomized killifish, Fundulus heteroclitus.
fish. II. Response to fracture under normal and
Proc. Soc. Exp. Biol. Med. 136:85-87.
acalcemic conditions. Acta Anat. 48:46-60.
Moss, M. L. 1963. The biology of acellular teleost Pang, P. K. T., R. W. Griffith, and M. P. Schreibman. 1973a. The pituitary gland and calcium mebone. Ann. New York Acad. Sci. 109:337-350.
tabolism in Fundulus diaphanus (Teleosteii). Gen.
Nadkarni, V. P., and G. Lapinsky. 1968. A histoComp. Endocrinol. 20:358-361.
chemical study of interrenal tissue and the corpuscles of Stannius of the rainbow trout, p. 19- Pang, P. K. T., and G. E. Pickford. 1967. Failure of
hog thyrocalcitonin to elicit hypocalcemia in the
20. Symp. Comp. Endocrinol., Banares Hindu
teleost fish, Fundulus heteroclitus. Comp. BioUniv.
chem. Physiol. 21:573-578.
Ogawa, M. 1967. Fine structure of the corpuscles of
Stannius and the interrenal tissue in goldfish, Pang, P. K. T., M. P. Schreibman, and R. W. Griffith. 19736. Pituitary regulation of serum calcium
Carassius auratus. Z. Zellforsch. 81:174-189.
levels in the killifish, Fundulus heteroclitus L.
Oguri, M. 1966. Electron-microscopic observations
Gen. Comp. Endocrinol. (In press)
on the corpuscles of Stannius in goldfish. Bull.
Peterson, G. L., and Z. H. Shehadeh. 1071. Changes
Jap. Soc. Sci. Fish. 32:903-906.
in blood components of the mullet, Mugil cephaOguri, M., and N. Takada. 1966. Effects of some horlus L., following treatment with salmon gonadomonic substances on the urinary and serum caltropin and methyltestosterone. Comp. Biochem.
cium levels of the snake-head fish Chana argus.
Physiol. 38B:451-458.
Bull. Jap. Soc. Sci. Fish. 32:28-31.
Olivereau, M. 1964. Corpuscles of Stannius in sea- Pflugfelder, O. 1953. Wirkungen der Epiphysectomie auf die Postembryonalentwicklung von Lewater eels. Amer. Zool. 4:415. (Abstr.)
bistes reticulatus Peters. Arch. Entw. Mech. Org.
Olivereau, M., and M. Chartier-Baraduc. 1965. Ac147:42-60.
tion de la prolactine chez l'anguille intacte et
hypophysectomizee. II. Effets sur les Electrolytes Pflugfelder, O. 1967. Weitere untersuchunger uber
kypho-lordose und Scoliose nach Zerstorung der
plasmatiques (sodium, potassium et calcium).
Epiphysen-region bei Fischen und Haushuhnern.
Gen. Comp. Endocrinol. 7:27-36.
Wilhelm Roux Arch. Entwicklungsmech. 158:170Olivereau, M., and J. Olivereau. 1970. Effect of pro187.
lactin in intact and hypophysectomized eels. VI.
Histological structure of interrenal. Water and Phillips, J. G., and P. J. Mulrow. 1959. Failure of
corpuscles of Stannius from winter flounder (Pseuelectrolyte metabolism. Z. Vergl. Physiol. 68:429dopleuronectes americanus) to synthesize adreno448.
corticosteroids in vitro. Nature (London) 184:558.
Orimo, H., T. Fujita, M. Yoshikawa, J. Abe, S.
Pickford, G. E. 1953. A study of the hypophysectoWatanabe, and K. Ontani. 1972. Ultimobranchial
mized male killifish, Fundulus heteroclitus (Linn.).
calcitonin of Anguilla japonica (Japanese eel), p.
Bull. Bingham Oceanogr. Collect. 14:4-41.
181. IV. Int. Congr. Endocrinol. Int. Congr. Ser.
Pickford, G. E., F. B. Grant, and B. L. Umminger.
No. 256.
1969. Studies on the blood serum of the euryhaOrimo, H., M. Ohata, M. Yoshikawa, J. Abe, S.
line Cypridont fish, Fundulus heteroclitus, adapted
Watanabe, M. Kotani, and T. Higashi. 1971.
to fresh or to salt water. Trans. Conn. Acad. Arts
Ultimobranchial calcitonin. II. Physiological role
Sci. 43:25-70.
of calcitonin. Igaku No Ayumi 79:480.
Pickford, G. E., R. W. Griffith, J. Torretti, E. HendPang, P. K. T. 1970. A study of the regulation of
ler, and F. H. Epstein. 1970. Branchial reduction
calcium, magnesium and phosphate metabolism
and renal stimulation of (Na, K)-ATPase by proin a teleost with acellular bone, Fundulus hetero-*
lactin in hypophysectomized killifish in fresh waclitus. Ph.D. Thesis, Yale University.
ter. Nature (London) 228:378-379.
Pang, P. K. T. 1971a. The relationship between
Rankin, J. C, D. K. O. Chan, and I. Chester Jones.
corpuscles of Stannius and serum electrolyte regu1967. Kidney function in the European eel, Anlation in killifish, Fundulus heteroclitus. J. Exp.
guilla anguilla. Gen. Comp. Endocrinol. 9:484Zool. 178:1-8.
485.
Pang, P. K. T. 19716. The effects of complete darkness and vitamin C supplement on killifish, Fun- Rasquin, P., and L. Rosenbloom. 1954. Endocrine
imbalance and tissue hyperplasia in teleosts maindulus heteroclitus, adapted to sea water I. Caltained in darkness. Bull. Amer. Mus. Natur. Hist.
cium metabolism and gonadal maturation. J.
104:363-425.
Exp. Zool. 178:15-22.
Pang, P. K. T. 1971c. Calcitonin and ultimobran- Robertson, D. R. 1970. Endocrinology of amphibian
chial glands in fishes. J. Exp. Zool. 178:89-100.
ultimobranchial glands. J. Exp. Zool. 178:101-114.
792
PETER K. T . PANG
Roy, B. B. 1964. Production of corticosteroids in
vitro in some Indian fishes with experimental histological and biochemical studies of adrenal cor'tex together with general observation on gonads
after hypophysectomy in O. punctatus. Calcutta
Med. J. 61:223-244.
Sandor, T., G. P. Vinson, I. Chester Jones, I. W.
Henderson, and B. J. Whitehouse. 1966. Biogenesis of corticosteroids in the European eel Anguilla
anguilla L. J. Endocrinol. 34:105-115.
Sano, T. 1960. Haematological studies of the culture
fishes in Japan. II. Seasonal variation in the blood
constituents of rainbow trout. J. Tokyo Univ.
Fish. 46:67-75.
Simmons, D. J. 1971. Calcium and skeletal tissue
physiology in teleost fishes. Clin. Orthop. Related
Res. 76:244-280.
Sokabe, H. 1968. Comparative physiology of the
renin-angiotensin system. J. Jap. Med. Ass. 59:502512.
Sokabe, H., S. Mizogami, and A. Sato. 1968. Role of
renin in adaptation of sea water in euryhaline
fishes. Jap. J. Pharmacol. 18:332-343.
Sokabe, H., H. Nishimura, M. Ogawa, and M. Oguri.
1970. Determination of renin in the corpuscles of
Stannius of the teleost. Gen. Comp. Endocrinol.
14:510-516.
van Someren, V. D. 1937. A preliminary investigation
into the causes of scale absorption in salmon
(Salmo salar Linne). Fish. Bd. Scotland Salmon
Fisheries. 1937(2). 12p.
Stanley, J. G. 1969. Seasonal changes in the electrolyte metabolism in the alewife, Alosa pseudoharengus, in lake Michigan, p. 91-97. Proc. 12th
Conf. Great Lakes Res.
Tomasulo, J. A. 1968. Structure of the Stannius corpuscles of the guppy during osmoregulation.
Anat. Rec. 160:441-442.
Urist, M. R., and O. A. Schjeide. 1961. The partition of calcium and protein in the blood of oviparous vertebrates during estrus. J. Gen. Physiol.
44:743-756.
Woodhead, P. M. J. 1968. Seasonal changes in the
calcium content of the bood of Arctic cod. J. Mar.
Biol. Ass. U.K. 48:81-91.
Woodhead, P. M. J. 1969a. Influence of oestradiol
3-benzoate upon the plasma content of calcium
and vitamin A aldehydes in the cod, Gadus mor-.
hua. J. Mar. Biol. Ass. U.K. 49:939-944.
Woodhead, P. M. J. 1969b. Effects of estradiol and
thyroxine upon the plasma content of a shark,
Scyliorhinus canicula. Gen. Comp. Endocrinol.
13:310-312.
Woodhead, P. M. J., and P. A. Plack. 1969. On the
levels of calcium and of vitamin A aldehyde in
the blood of arctic cod. J. Mar. Biol. Ass. U.K. 48:
93-96.
Woodhead, P. M. J., and A. D. Woodhead. 1964.
Seasonal changes in the physiology of the cod in
relation to its environment. I. Seasonal changes in
the physiological reactions of Barents Sea cod,
Gadus morhua L., particularly affecting migration
and maturation. ICNAF Envir. Symp. Ser. No.
1255A. Contrib. No. F-6a. 25 p.
Yamada, J. 1961. Studies on the structure and
growth of the scales in goldfish. Mem. Fac. Fish.
Hokkaido Univ. 9:181-226.