Volumetric Analysis of Glomerular Size in
Kidneys of Mammals Living in Desert,
Semidesert or Water-Rich Environment
in the Sudan
By I. Munkacsi, M.D., Ph.D., and M. Palkovits, M.D.
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• Adaptations to desert life have attracted
much interest in the past forty years.1"5 In
addition to the physiological aspects of
this subject, there are morphological signs of
adaptation to an arid environment in the
kidneys of desert animals when compared to
the kidneys of animals that require free access to water for their normal life. One of the
distinguishing features of the former is the
long renal papilla which extends beyond the
pelvis of the ureter and projects into the
proximal portion of the ureter.0"8 The renal
cortex forms a relatively thin layer around
the thick medulla. The long renal papilla is
composed of deeply situated juxtamedullary
nephrons with long thin segments of the
loops of Henle. These elongated, deeply
placed nephrons make such kidneys so
efficient that desert mammals use only onefourth of the amount of water needed by
water-requiring mammals in order to excrete
the same amount of urea.
According to the generally accepted
countercurrent hypothesis the concentration
of the urine takes place in the renal papilla.
Here the loops of Henle act as a countercurrent multiplier and the vasa recta as a
countercurrent diffusion exchanger, producing a steadily increasing osmotic gradient
from cortex to papilla. The longer the loops
of Henle and accompanying vasa recta,
the more effective is the countercurrent
From the Department of Anatomy, University of
Khartoum, Khartoum, Sudan and Department of
Anatomy, Medical University of Budapest, Budapest,
Hungary.
Accepted for publication March 23, 1965.
Circuhiion Research, Vol. XVII, October 1965
mechanism. In the desert and semidesert
animals the deep nephrons, and especially
their thin segments, are extremely long in
the inner zone of the medulla and in this
zone the vasa recta are evenly distributed.
Such juxtamedullary nephrons with their
large juxtamedullary glomeruli seem to be
essential to species inhabiting the desert and
semidesert in order to conserve water by
secreting a highly concentrated urine. Therefore the striking length of the deep nephrons
can be considered as a sign of adaptation
to arid environment.
The large size of the juxtamedullary glomeruli has been well-known since Bowman's
investigations. Apart from the shunt mechanism in pathological conditions described by
Trueta et al.8 and recently reinforced by
Adebahr, 10 ' u the juxtamedullary glomeruli
present a larger filtration surface. Hanssen12
stated: "the glomerular filtration rate of the
juxtamedullary nephrons approximates eight
times that of nephrons from the outer cortex."
The size of glomeruli is related probably to
the demands for filtration and this seems to
be supported by the observation that after
unilateral nephrectomy the glomeruli enlarge
in the remaining kidney. In the kidneys of
the desert and semidesert species investigated
here, small cortical and large juxtamedullary
glomeruli could be observed in sections by
simple microscopic examination. We have
supposed that the large size of the juxtamedullary glomeruli indicates increased functional
capacity in these species8 and, apart from
the other properties of the juxtamedullary
nephrons, represents a sign of adaptation to
the increased demands of the arid environ303
304
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ment. In order to compare the difference in
size between the cortical and juxtamedullary
glomeruli, statistical volumetric analyses were
made separately in the cortex and in the
corticomedullary junction in the kidneys of
the desert-living and water-requiring mammals and the results were compared with
each other.
Mollendorff,13 and more recently Zolnai and
Palkovits,14115 reviewed various investigations
of glomerular volume. It was found that
the volume of the glomeruli is influenced
by several factors including the size and
weight of the body and kidney, the age and
diet of the animal, and its phylogenetic
position. The relation between the size of
the glomeruli and the body and kidney weight
does not seem to be proportional in mammals
when species are compared with each other
and this relation can be expressed mathematically only within a given species. Rytand10
assumed that glomeruli are perfectly spherical
and calculated glomerular volumes in several
species including the desert rat. He found
that total glomerular volume, body weight,
and kidney weight are closely related. The
heavier the kidney or the greater the body
weight, the larger are the glomeruli. He also
found that in a desert rat (Dipodomys
mohaviensis) the total glomerular volume was
low per unit of kidney although the kidney
weight to body weight ratio was normal.
Khalil and Tawfic" found that, in other desert
rats (Jaculus jaculus and Gerbillus sp.), the
ratios of kidney weight to body weight, and
glomerular volume to body weight, were
normal. These authors did not measure
separately the cortical and juxtamedullary
glomeruli, and glomerular volumes were calculated on the assumption that the glomeruli
are of uniform size throughout the renal
cortex.
Although kidney structure depends largely
upon the evolutionary history of a species,
environmental factors may also affect structure. In this investigation we have compared
the glomerular volumes of several mammals
in relation to their special habitats.
MUNKACSI,
PALKOVITS
Methods
SPECIES INVESTIGATED
Kidneys of four mammalian species were studied, including a desert rodent, the jerboa (Jaculus
jaculus); the laboratory white rat (Rattus norvegicus); a semidesert-inhabiting subprimate,
the "bush baby" (Calago senegalensis senegalensis) and a water-requiring primate, the grivet
monkey (Cercopithecus aethiops aethiops). The
jerboa is a rodent that lives in the desert and
semidesert plain northwards from Khartoum, is
fully adapted to desert life and can withstand
severe dehydration for several months.8'17 The
animals used were captured in the semidesert
outside Khartoum North and on the north bank
of the Blue Nile. The laboratory white rat can
withstand dehydration for only three days at
high temperature and low relative humidity and
it must have free access to water.
Bush babies can withstand a substantial degree of dehydration. During experimental dehydration they were fed only on dry seeds and milk
powder for 12 days. Their distribution in the
Sudan coincides with the low-rainfall savannah
woodland region and the northern population
limit follows the 400 mm isohyet. The animals
used in this study came from the Nuba mountains, situated some 12° N of the equator, where
there is no rain for four to five months of the
year, and where the vegetation becomes very dry.
Grivet monkeys cannot withstand dehydration for
long periods and abundant water is essential for
their survival. Wherever they are found their
habitat contains pools, lakes or rivers and, although they may roam considerable distances,
they never go far from water.
VOLUMETRIC ANALYSIS OF GLOMERULAR SIZE
Quantitative statistical measurements of the
relative volumes of glomeruli were made by the
method of Palkovits and Zolnai.18 In histological sections the glomeruli appear as elliptical
outlines within Bowman's capsule. In every glomerulus a long (L) and a short (B) diameter
can be drawn. The glomerulus can be considered
as a rotation ellipsoid resulting from an imaginary
rotation about the long axis. In this case the
volume of the ellipsoid can be calculated from the
formula:
vol = ^-
which is based upon the two known axial measurements, L and B, while the third axis is assumed
equal to one-half
of B. According to Palkovits
and Zolnai1S measurements of glomerular volume
are more accurate when computed from two
axial measurements than when computed from
mean intercepts with random chords. The logarithOrculation Research, Vol. XVII, October 1965
305
VOLUMETRIC ANALYSIS OF GLOMERULAR SIZE
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mic values of the calculated volumes were used
for graphs and statistical analysis. The volumes
of glomeruli show a "lognormal" distribution
when measured by this method and therefore
they can be classified into logarithmic classes
and these can be analyzed statistically in a distribution curve. In Hintzsche's 19 concept, if the
volumes of the glomeruli are "lognormal" then
the distribution curve obtained by logarithmic
classification is regular.
In histological sections the sizes of the glomeruli vary widely depending on the plane of
section. Glomeruli cut along the short axis appear
as circles whereas others, in which only a small
part of the glomerulus has been cut in tangential
section, appear as small ellipses or circles. Because
the volumetric measurements are related to rotating bodies, different sizes of ellipsoid volumes
will be obtained depending upon the size and
plane of the section measured. In these circumstances a sufficiently large number of measurements (at least 300) must be taken to obtain
statistically valid figures. Neither the mean volume
of the ellipsoids, nor the curve showing the distribution of the different sizes, is absolute and
so neither can give the absolute volume of the
glomeruli. Hence these relative figures can be
used only to make comparisons.
The animals used in this investigation were
kept, prior to sacrifice, for at least a week on
their normal diet and had free access to water.
Body weights and weight of one kidney were
respectively: for the jerboa, 60 g and 0.16 g; for
the white rat, 180 g and 0.62 g; for the bush
baby, 160 g and 0.55 g; and for the grivet monkey
1834 g and 5.00 g. The animals were killed with
ether and one kidney from each specimen was
fixed in 4% formalin, embedded in paraffin wax,
sectioned at 17 fi and stained with hematoxylin
and eosin. The plane of section was adjusted so
that the interlobular arteries were cut along their
long axis. In order to measure the cortical and
juxtamedullary glomeruli, on each of 20 slides,
the glomeruli along the corticomedullary junction
were covered with India ink under a stereomicroscope and, on another 20 slides, the cortical
glomeruli were covered similarly.
It should be noted that, in histological sections,
the separation of cortical glomeruli from juxtamedullary glomeruli cannot be done with complete accuracy and several glomeruli may be
counted in the wrong zone. For this reason the
distribution curves for volumes may show two
peaks for glomeruli in either the cortex or juxtamedullary region, a small secondary peak representing the misplaced glomeruli.
The sections were projected, prior to measurement, on an opaque glass plate so that the glomeruli were magnified 250 times and the image
Circulation Research, Vol. XVII, October 196)
was then measured with a millimeter ruler. Three
hundred measurements were made in each species. For classification the logarithms of the glomerular volumes were calculated and plotted as
the abscissa, and the percentage numbers of
each volume as the ordinate. The distribution
curve obtained shows the degree of variation in
glomerular size. A high curve with steep slope
indicates uniformity of size, whereas variations of
glomerular size result in an even slope or, instead
of a peak, a plateau. A double peaked curve
indicates glomeruli of significantly different sizes
and this is the case when the juxtamedullary
glomeruli differ significantly in size from those of
the cortex.
The ratio of glomerular volume to cortex volume was measured according to the method of
Palkovits and Zolnai.18 The sections used for
measuring volumes were projected onto an opaque
glass plate at the specified magnification of 250
times. This plate had on it a grid of one hundred
squares, each with area of one square centimeter.
The number of glomeruli falling within the intersections of the grid lines was counted. Twenty
different fields were counted in each specimen
and the mean was calculated. The numbers obtained are regarded as representing the percentage frequency of occurrence of glomeruli and
permit computing the ratio between glomerular
volume and total tissue volume in the renal
cortex.
Observations
In the kidney of the jerboa comparatively
small glomeruli were found; the average
volume of the cortical and juxtamedullary
glomeruli together is 9550 /u,3. The average
volume of the cortical glomeruli is 7718 /J,3
and of the juxtamedullary glomeruli 15520 /u,3,
the latter being twice as big as the former
(table la). The curve for the cortical glomeruli shows a regular distribution in volume
(fig. la). The curve of the juxtamedullary
glomeruli is placed far to the right side of
the cortical curve indicating that at the corticomedullary junction the glomeruli have, on
the average, a greater volume. Both distribution curves are steep and regular indicating
uniformity of volume. The curve for the
juxtamedullary glomeruli is wider than that
for the cortical glomeruli. Also, the middle
logarithmic groups of volumes contain 33%
of cortical but only 27% of juxtamedullary
glomeruli. Hence the latter glomeruli have
a greater range of volume. The position of
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I
o
(d) Crivet monkey
Cortical glomeruli
Juxtamedullary glomeruli
Average, all glomeruli
_
1
1
_
(b) Laboratory white rat
Cortical glomeruli
Juxtamedullary glomeruli
Average, all glomeruli
(c) Bush baby
Cortical glomeruli
Juxtamedullary glomeruli
Average, all glomeruli
—
—
—
(a) Jerboa
Cortical glomeruli
Juxtamedullary glomeruli
Average, all glomeruli
3.3
_
_
4
4
1
—
1
3.4
13
_
8
_
3
—
1
3.5
_
25
1
14
5
—
3
3.6
_
_
27
1
20
13
1
9
3.7
17
5
24
_
33
3
21
3.8
15
23
7
31
3.9
Clomerular Volumes in Four Species Inhabiting Different Environments
5
4
4
2
12
18
15
4.0
1
12
1
3
3
2
7
23
7
1
27
3
8
5
7
1
25
6
26
4
14
11
11
1
14
2
Log volume
4.1
4.2
4.3
TABLE 1
4
1
4
10
26
14
20
—
6
3
4.4
7
4
11
!
4
26
28
29
—
2
1
4.5
4.9
5.0
1
4
4
1
4
3
—
1
1
— —
_
_
_
_
_ _ _ _
4.8
25 30 22
12 20 2 8
2 8 2 3 10
_
1
3
11
8
!
4.7
—
—
—
_
_
_
5.1
8
25
13
2
6
8
—
4
2
— — — — —
_ _ _ _ _ _
_
1 i
16
19
14
_
4.6
—
1
—
—
—
—
—
—
—
—
—
—
5.2
4.7348
4.8418
4.7503
3.8347
4.2416
3.9195
4.4738
4.5587
4.5210
3.8875
4.1909
3.9799
54300
69470
56280
6835
17450
8310
29770
36200
33210
7718
15520
9550
Average
log
O
•v
o
I
c
o
307
VOLUMETRIC ANALYSIS OF GLOMERULAR SIZE
meruli. The ratio of the glomemlar volume to
the cortex volume is 6.93% and this is similar
to that of the white rat but lower than those of
the other species investigated.
The glomeruli of the laboratory white rat
are much bigger than those of the jerboa.
the average of both cortical and juxtamedullary glomemli indicates that most of the
glomeruli are of cortical type. The average
curve lies close to the cortical curve and
only 10% of the total number of glomeruli
belong to the class of juxtamedullary gloiO
11.
a
C.
30
20
/
,
1
M
\\ /
to-
/
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s
log ml 3,3
ii
J5
3,6
i,l V
t''
X
'
\
\
\
\
\
\
J
3,9 ifl i,l
V 4.3
i
,4 4.5
3.6 3.7 3,1 3.9 4,0 t.l 4,2 i,3 i,i
3.( 3,5 3.6 3.7 3fi 3.9 ifl tj
4.6
«7
<5
4P 5.0 57
5?
i,S i,6 i.7 i,S i.9 5,0 5,|
4> <,j if. ifi IIS >.}
V
5fi S'l
3J
JO
20
IS-
10\
ifi
i d 4/ 5,2
FIGURE 1
Distribution curves of glomemlar volumes in kidneys of: (a) jerboa, (b) laboratory white rat,
(c) bush baby, and (d) grivet monkey. For each animal the curves are labelled similarly. C:
volume of cortical glomeruli. J: volume of juxtamedullary glomeruli. T: volume of the cortical
and juxtamedullary glomeruli together.
Circulation Research, Vol. XV11, October 1965
308
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These two animals are comparable because
both are rodents although the body weight of
the white rat examined was three times that
of the jerboa. The average volume of the
cortical and juxtamedullary glomeruli together
in the white rat is 33210 /z,3. The average
volume of the cortical glomeruli is 29770 /LA3
and of the juxtamedullary ones is 36200 fi3
(table l b ) . The juxtamedullary glomeruli are
only 21% bigger than the cortical glomeruli.
The distribution curve obtained from the
logarithms of the glomerular volumes of the
white rat show that the glomeruli are, in
general, bigger than those of the jerboa (fig.
lb). The curve of the cortical glomeruli is
steep and has a plateau at the top. Analysis
of this curve indicates rather uniform
glomerular volume but, even so, most of
the glomeruli are grouped in two different
volumes which are very close to each other.
The curve of the juxtamedullary glomeruli
is placed only slightly to the right side of the
cortical curve, is wide and is also extensive
enough to include the sizes of most of the
cortical glomeruli. This indicates that, at the
juxtamedullary junction, the glomeruli differ
in volume to some degree but those which
are bigger are fewer in number. The ratio
of the glomerular volume to cortex volume
is 6.90% in the white rat and is nearly the
same as in the jerboa.
In the bush baby the average volume of the
cortical and juxtamedullary glomeruli together is small, 8310 /u,3, and is similar to that
of the jerboa. The average volume of the
cortical glomeruli is 6835 /A3 and of the juxtamedullary glomeruli 17450 ft3, the latter being
169% larger than the former (table lc). The
distribution curves in figure lc show this
difference clearly; the curve for juxtamedullary glomeruli is placed five logarithmic
classes to the right of the curve for cortical
glomeruli. Most of the glomeruli are found in
the middle logarithmic groups of each curve.
The position of the average curve of both
cortical and juxtamedullary glomeruli is nearer
to the cortical curve and has a low slope in
the region of the juxtamedullary glomeruli
representing only 8% of the total number of
MUNKACSI, PALKOVITS
glomeruli. The ratio of the glomeruli in the
cortex is 7.73% which shows that, although
the glomeruli are rather small, their percentage
distribution in the cortex is relatively greater
than that in the other species examined.
In the kidney of the grivet monkey comparatively large glomeruli are found, the
average volume of the cortical and juxtamedullary glomeruli together being 56280 /A3. The
average volume of the cortical glomeruli is
54300 /x3 and of the juxtamedullary glomeruli 69470 (Is (table Id). The juxtamedullary
glomeruli are 28% bigger in volume than the
cortical ones. This percentage difference is
similar to that in the white rat where the
juxtamedullary glomeruli are 21% bigger. The
shape of the distribution curve obtained from
the logarithm of the glomerular volumes shows
that the curves of both the cortical and
juxtamedullary glomeruli are high with steep
slope (fig. Id), indicating that the sizes of
both types of glomeruli are fairly uniform.
The curve of the juxtamedullary glomeruli is
placed only one to two logarithmic classes
to the right of the curve of the cortical
glomeruli indicating that the juxtamedullary
glomeruli are only slightly larger. The curves
have double peaks indicating that, although
the difference in volume between the cortical
and juxtamedullary glomeruli is not great,
the number of juxtamedullary glomeruli exceeds (23%) that in the other species examined. The location of these glomeruli is
not limited exactly to the corticomedullary
junction and several glomeruli might be
counted as belonging to one zone when
they belong, in fact, to the other zone. The
percentage distribution of the glomeruli in
the cortex is 7.46%. This percentage is less
than that of the bush baby and higher than
that of the jerboa and the white rat.
Discussion
If the phylogenetic relationship of these
four species is considered, then the jerboa
must be compared with the white rat, and
the bush baby with the grivet monkey. In
the jerboa and white rat the average volumes
of the cortical and juxtamedullary glomeruli
Circulation Research, Vol. XVII, October 1963
VOLUMETRIC ANALYSIS OF GLOMERULAR SIZE
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and their percentage distributions in the
cortex are similar. The body weight of the
white rat (180 g) was three times that of
the jerboa (60 g). Similarly the average
volume of the cortical and juxtamedullary
glomeruli together in the white rat (33210 /A3 )
was 3.47 times that of the jerboa (9550 /x3).
Zolnai and Palkovits14 found that four-monthold white rats, which have a body weight similar to that of the jerboa, have similar average
glomerular volumes. The percentage distribution of the glomeruli in the cortex is also similar in both animals (white rat, 6.90%; jerboa,
6.93%). There is a significant difference between the volumes of the cortical and juxtamedullary glomeruli in these two animals. In
the jerboa the juxtamedullary glomeruli are
101% bigger than the cortical ones and, in the
white rat, only 21%.
The average volume of the glomeruli in
the bush baby is relatively twice that of the
grivet monkey when compared to body
weight. The weight of the bush baby (160 g)
is 11.5 times smaller than that of the grivet
monkey (1834 g) and the average volume of
the glomeruli in the bush baby (8310 /A3)
is only 6.8 times smaller than that of the
grivet monkey (56280 /A 3 ). The percentage
distribution of the glomeruli in the cortex is
higher in the bush baby (7.73%) than in the
grivet monkey (7.46%). There is also a significant difference between the volumes of the
cortical and juxtamedullary glomeruli in these
two animals. In the bush baby the juxtamedullary glomeruli are 169% bigger than the
cortical ones but, in the grivet monkey, they
are only 28% bigger.
As a result of these comparisons it can
be stated that no relation can be shown between the average glomerular volumes and
the body weights of these animals. The
average glomerular volumes do not seem to
be proportional to body weight and a similar
conclusion holds for the average volume of
the glomeruli and the kidney weight. The
difference in volumes between the cortical
and juxtamedullary glomeruli indicates a
difference between the animals of arid and
water-rich habitat.
Circulation Research, Vol. XVII, October 1965
309
If the animals used in this study are
grouped according to their habitats then it
can be observed that in the grivet monkey
and white rat the difference in volume between the cortical and juxtamedullary glomeruli is much less than in the jerboa and
the bush baby. Considering the similarity of
habitat of these two groups of animals and
the fact that other renal structures are
similar,8 in spite of phylogenetic and other
differences, it is reasonable to suppose that
those animals which live in a water-rich habitat have a small difference in volume between
the cortical and juxtamedullary glomeruli
and those which live in an arid habitat have
a big difference.
The large juxtamedullary glomeruli of the
jerboa and of the bush baby indicate a large
filtration surface in the juxtamedullary region
of the kidney and a pronounced functional importance of these structures in animals that live
in an arid habitat and can stand dehydration
well by producing a highly concentrated urine.
Munkacsi8 found that the juxtamedullary glomeruli and the related vasa recta of desert
animals play an important role in the regulation of blood circulation under conditions of
dehydration. In the kidneys of the jerboas
captured in the field in dry season, or kept
on dry grains without access to water for
36 days, the juxtamedullary glomeruli and
the vasa recta were filled with blood as shown
by the benzidine reaction or filled with India
ink when injected via the arterial system,
while the cortical glomeruli and the related
capillary bed appeared to be ischemic. In
the semi-desert living bush babies, deprived
of water for three days, the cortical ischemia
was less pronounced but still the juxtamedullary glomeruli and the vasa recta were very
well filled.
The water-requiring animals, such as the
grivet monkey and laboratory white rat, deprived of water for three days, seemed to
have incomplete filling of cortical vessels by
blood or India ink but the juxtamedullary
glomeruli were still very well filled. A juxtamedullary circulation with combined cortical
ischemia occurs in dogs20'21 and in the grivet
310
MUNKACSI, PALKOVITS
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monkey only after inducing dehydration by
ligation of the pylorus for 48 hours. During
this period, owing to vomiting, a combined
water and solute loss with circulatory failure
develops. In the instances of the desert and
semidesert animals subjected to dehydration
by water deprivation the well filled juxtamedullary glomeruli and the related vasa
recta may be interpreted as a sign of the
overactivity of the tubules in the renal medulla. This would imply an overactivity of the
juxtamedullary nephrons whilst the glomeruli
and the blood vessels of the short cortical
nephrons, in the semidesert animals, contain
little or no blood, apparently with diversion
of filtration towards the juxtamedullary glomeruli.
The deep nephrons are more effective in
the mechanism of urine concentration and
this is one of the reasons for the ability of
the desert and semidesert animals to withstand dehydration better than the waterrequiring animals. The deep nephrons and the
related vasa recta are long in the desert and
semidesert animals and the juxtamedullary
glomeruli are large. The deep nephrons of
the water-requiring animals are relatively
shorter than those of the desert and semidesert
animals. In the jerboa and bush baby the
deep nephrons are very well developed. The
renal cortex is thin, the medulla is thick,
and the renal papilla projects far into the
ureter. The medullary substance contains well
developed vasa recta and the efferent arterioles of the juxtamedullary glomeruli possess
a thick muscular layer. Also, the distribution
of the vasa recta bundles in the outer zone
of the medulla is distinctive in the desert
animals. The volumetric analysis of the
glomerular volume of the desert and semidesert animals reinforces the importance of
the juxtamedullary glomeruli and their large
size can be considered as a sign of adaptation
to arid environments.
Summary
The glomerular volumes in the kidneys
were studied in four species of mammals,
including a desert rodent, the jerboa (Jaculus
jaculus); the laboratory white rat (Rattus
norvegicus); a semidesert-living subprimate,
the "bush baby" (Galago senegalensis senegalensis); and a primate, the grivet monkey
(Cercopitheus aethiops aethiops). The measurements of volume were made according
to the method of Palkovits and Zolnai which
gives quantitative statistical values for the
relative volumes of the glomeruli. An exact
relationship between the average of the
glomerular volumes, kidney weight, and body
weight was not found in these different
mammals when compared to each other. If
the average volumes of the cortical and of
the juxtamedullary glomeruli are compared
separately then it is seen that the desert-living
animals have a much bigger difference in
volume between the cortical and the juxtamedullary glomeruli than those animals which
require free access to water. In the kidney
of the desert rodent (jerboa) the difference
in volume between the cortical and the
juxtamedullary glomeruli is 101% and, in
the semidesert-living "bush baby," 169%. On
the other hand the corresponding difference
of volume in the laboratory white rat is only
21% and in the grivet monkey 28%. Considering the great functional importance of
the juxtamedullary glomeruli and deep
nephrons of the kidney in relation to dehydration, the large size of these structures can
be regarded as an adaptation to life in an
arid environment.
Acknowledgment
We express our thanks to Professor H. Butler,
Anatomy Department, University of Saskatchewan,
Saskatoon, Canada for reading the manuscript.
References
1. HOWELL, A. B., AND GERSH, I.: Conservation of
water by the rodent Dipodomys. J. Mammal.
16: 1, 1935.
2.
SCHMIDT-NIELSEN,
B., SCHMIDT-NIELSEN,
K.,
BHOKAW, A., ANT> SCHNEIDERMANN, H.: Water
conservation in desert rodents. J. Cellular
Comp. Physiol. 32: 331, 1948.
3.
SCHMIDT-NIELSEN,
B.,
AND SCHMIDT-NIELSEN,
K.: The water economy of desert animals.
Sci. Monthly 69: 180, 1949.
4.
SCHMIDT-NIELSEN,
B.,
AND SCHMIDT-NDZLSEN,
K.: A complete account of the water metabCirculation Research, Vol. XVII, October 196S
311
VOLUMETRIC ANALYSIS OF GLOMERULAR SIZE
olism in kangaroo rats and an experimental
verification. J. Cellular Comp. Physiol. 38:
165, 1951.
5. SCHMIDT-NIELSEN, K.: Desert Animals. Physiological Problems of Heat and Water. Oxford,
Clarendon Press, 1964.
6. SPERBER, I.: Studies on the mammalian kidney.
Zoologiska Bidrag Fran Uppsala 22: 249, 1944.
7. KHALIL, F., AND TAWFIC, J.: Some observations
on the kidney of the desert rat, /. jaculus and
G. gerbillus and their possible bearing on the
water economy of these animals. J. Exptl.
Zool. 154: 259, 1963.
8. MUNKACSI, I.: The vascular and tubular structure of the mammalian kidney in relation to
water conservation. Ph. D. thesis, University
of Khartoum, Sudan, 1964.
14.
Downloaded from http://circres.ahajournals.org/ by guest on June 14, 2017
11.
ADEBAHR, G.: Morphologische Besonderheiten an
der arteriellen Strohmbahn der juxtamedullaren Glomerula in der Niere von Ratte und
Kaninchen. Z. Zellforsch. mikroskop. anat. Abt.
Histochem. 59: 577, 1963.
12.
15. ZOLNAI,
13.
AND PALKOVITS,
M.:
Glomerulo-
B., AND PALKOVITS,
M.:
Glomerulo-
metrische Untersuchungen wahrend des Lebens. Verhandl. deut. Anat. Ces., Versammlung
in Wein. 1964. In press.
16.
RYTAND, D. A.: The number and size of mam-
malian glomeruli as related to kidney and to
body weight with methods for their enumeration and measurement. Am. J. Anat. 62: 507,
1938.
17.
KIRMIZ,
J. P.:
Adaptation
de
la gerboise
au
milieu desertique. Etude comparee de la
thermoregulation chez la gerboine (Dipits
egypticus) et chez la rat blanc. Alexandria,
Societe de publications Egyptiennes, S. A. E.
1962.
18.
PALKOVITS,
M., AND ZOLNAI,
B.:
Quantitativ-
histologische Methode zur statistischen Untersuchung des Volumens der Nierenglomeruli
und deren Anteil an der Nierenrinde. Z.
Wiss. Mikroskopie. 65: 342, 1963.
19. HINTZSCHE, E.: Biologische Statistik durch materialgerechte Klasseneinteilung. Schweizz. Z.
Volkswirtschaft u. Statistik 82: 433, 1946.
20.
GOMOBJ, P., MUNKACSI, I., NACY, Z., TAKACS,
L., AND KALLAY, K.: Ischaemia and arterio-
venous anastomoses of the kidney in shock,
haemorrhage, dehydration and arterial hypoxia
on dogs. Acta Med. Hung. 18: 119, 1962.
HANSSEN, O. E.: The frequency of temporarily
inactive glomeruli in mice under physiologic
condition. Acta Pathol. Microbiol. Scand. 53:
253, 1961.
B.,
metrics 11. New data concerning the growth
of the glomeruli in the albino rat. Acta
Morphol. Acad. Sci. Hung. In press.
9. TRUETA, J., BARCLAY, A. E., DANIEL, P. M.,
FRANKLIN, K. S., AND PRICHARD, M. M. L.:
Studies of the Renal Circulation. Oxford,
Blackwell Scientific Publications, 1947.
10. ADEBAHR, G.: Bietrag zur Morphologie der Vasa
afferentia und efferentia der juxtamedullaren
Glomeruli der menschlichen Niere. Z. mikr.anat. Forsch. 68: 48, 1962.
ZOLNAI,
MOLLENDORFF, W.: Handbuch der mikroskopis-
MUNKACSI, I., NACY, Z., TAKACS, L., KALLAY,
K., AND GOMORI, P.: Vascular shunts in the
chen Anatomie des Menschen. vol. 7. Berlin,
Springer-Verlag, 1930.
renal cortex of the dog. Rev. Can. Biol. 22:
353, 1963.
Circulation Research, Vol. XVII, October 1963
21.
Downloaded from http://circres.ahajournals.org/ by guest on June 14, 2017
Volumetric Analysis of Glomerular Size in Kidneys of Mammals Living in
Desert, Semidesert or Water-Rich Environment in the Sudan
I. MUNKáCSI and M. PALKOVITS
Circ Res. 1965;17:303-311
doi: 10.1161/01.RES.17.4.303
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