Increased Weight of the Liver in Wistar Albino Rats with
Induced,and Transplanted Ttlmors
Eleanor H. Yeakel,
Ph.D.
(From the Wistar Institute o] Anatomy and Biology, Philadelphia 4, and the Department ol Anatomy,
Hahnemann Medical College and Hospital, Philadelphia 2, Pa.)
(Received for publication January 12, 1948)
In a report on changes with age in the livers of
Wistar albino rats (4), it was pointed out that the
average weight of the livers of old (600 to 1,000
days) females with spontaneous tumors elsewhere
in the body was significantly heavier than that of
tumor-free old females, and of younger females of
comparable body length. In old male rats, in
which growths rarely occurred, there was no such
increase in the average weight of the liver. Comparison of the weight of mammary gland tumors
with the weight of the host's liver revealed no correlation, except that enlargement of the liver was
found when the weight of the growth exceeded 30
gm.
The work presented here was undertaken to determine whether the apparent influence of tumors
on the weight of the liver, as indicated above, was
confined to spontaneous growths and occurred only
in females, and whether it was correlated with
old age.
TABLE I :
PROCEDURE
Male and female Wistar albino rats were used.
The experimental animals bore subcutaneously
either a transferred fibrosarcoma, or a primary
tumor induced by injection of methylcholanthrene.
The growths did not metastasize. The exact ages
of the rats were not calculated, but none was older
than 300 days at death. When the animal was
killed, the body length from nose to anus was
measured, and the subcutaneous tumor, the carcass without the tumor, and the liver, were weighed.
The weight of the liver relative to body weight and
to body length was calculated. Corresponding control values were taken from the 21 to 300 day old
rats dissected for the study of aging (4).
RESULTS
The data for the experimental female animals
are presented in Table I, and for the males, in
Table II. The rats are listed in order of increasing
WEIGHT OF TUIIOR AND OBSERVED AND RELATIVE WEIGHT OF THE LIVER IN FEMALES
Body weight
Body length,
(less tumor),
Rat
mm.
gin.
1
202
231
2
225
342
3
214
270
4
207
201
5
176
151
6
175
138
7
217
210
8
207
244
9*
143
81
10
196
222
11
188
174
12"
167
98
13
213
239
14
199
197
15
207
212
16
201
204
17
211
230
18
194
166
19
200
200
20
199
211
21
191
173
22
200
185
23
211
265
* Body length less than 180 mm.
t Tumor inoculated, but failed to grow.
Tumor weight,
gin.
Neg. t
2
5
6
10
13
27
32
36
40
46
60
60
61
62
71
71
81
84
89
95
111
123
Liver weight,
gin.
8.65
10.78
9.39
9.30
7.53
7.04
9.28
12.94
5.26
11.29
9.58
7.72
12.60
12.06
14.28
11.58
19.12
11.32
10.64
13.37
11.69
11.98
14.38
Liver
Liver
B.L.
0.0428
0.0479
0.0439
0.0449
0.0428
0.0402
0.0428
0.0625
0.0368
0.0576
0.0510
0.0462
0.0592
0.0606
0.0690
0.0578
0.0906
0.0584
0.0534
0.0672
0.0612
0.0599
0.0681
B.Wt.
0.0374
0.0315
0.0348
0.0462
0.0499
0.0510
0.0442
0.0530
0.0650
0.0512
0.0550
0.0787
0.0527
0.0610
0.0673
0.0567
0.0831
0.0682
0.0534
0.0633
0.0676
0.0686
0.0542
392
Downloaded from cancerres.aacrjournals.org on June 17, 2017. © 1948 American Association for Cancer
Research.
Yeakel--Liver Weight Increase in Rats with Tumors
tumor weight. The individual weights of the liver
divided by the body length in control and experimental rats are plotted against the body length in
the graphs.
From Table I it may be seen that no consistent
relationship existed between the weight of the
tumor and the actual weight of the liver, or its
weight relative to body weight. With the exception
of two rats (marked with an asterisk), the liver
values relative to body length were greater than
0.0500 when the tumors weighed more than 30 gm.
Further growth of the tumor was not accompanied
by a proportional increase in liver size. The graph
for the females shows that the liver weights of animals with tumors under 30 gm. lay within the
range established by the normal controls. The two
rats with heavier tumors but normal relative liver
weights were small animals, with body lengths less
than 180 mm. The relative weights in the remaining female hosts were clearly higher than normal.
Less clear-cut but similar results were found in
male rats. The liver weights relative to body length
were greater than 0.0500 when the tumors weighed
more than .30 gm. in all but 4 of the experimental
animals (Table II). Three of these were small animals, with body lengths less than 180 mm. In the
graph it may be seen that while some livers were
very heavy compared with control values, there is
a considerable spread of the relative weights, and
393
overlapping with the control group. However, the
average relative weight of the livers of tumor-bearing males (over 190 mm. body length) is 0.0632 ___
0.0021, and of control males of the same range of
body length, 0.0499 + 0.0010; the standard error
of the difference between the means being 0.0023,
the actual difference is significant statistically.
DISCUSSION
The results of this experiment extend the earlier
observations (4) on old female rats with spontaneous tumors to include adult animals of both sexes
with induced and transplanted neoplasms. The relationship between the presence of a tumor and an
increase of liver weight is clearer, however, in female rats than in males.
There are several interesting parallels with the
results obtained by McEwen and Haven (1): (a)
These authors, using young male rats inoculated
subcutaneously with carcinosarcoma 256, found a
significant increase in the percentage of water in
the liver, providing the tumor exceeded a critical
weight (10 gin.). (b) The percentage of water did
not increase with further growth of the tumor.
(c) The weight of the liver relative to body weight
did not differ significantly from the control figures.
In the calculations reported in the present paper,
the use of body length rather than body weight as
a measure of size revealed a relation between the
TABLE I I : WEXGHT Or TUMOR AND OBSERVED AND RELATIVE WEIGHT OF THE LIVER IN MALES
Rat
1
2
3
4
5
6*
7
8
9
10
11
12
13
14"
15"
16
17
18
19
20
21
22
23
24
25
26
Body length,
ram.
176
165
162
216
221
172
180
217
216
204
213
185
220
171
159
211
228
221
198
202
194
205
206
215
226
219
Body weight
(less tumor),
gin.
133
110
293
288
311
131
197
293
255
220
264
217
332
129
89
246
327
293
206
194
189
224
206
282
319
245
Tumor weight,
gin.
12
26
27
31
32
33
39
42
42
42
43
44
44
46
47
48
50
54
60
67
72
75
81
83
96
126
Liver weight,
gin.
6.64
7.56
5.52
13.84
13.36
6.47
14.89
14.74
12.16
11.20
11.51
15.75
16.40
7.t9
4.93
12.05
15.62
14.07
9.09
11.76
11.57
13.85
13.07
17.81
16.59
14.22
Liver
Liver
B.L.
0.0377
0.0458
0.0341
0.0641
0.0605
0.0376
0.0827
0,0680
0.0563
0.0549
0.0540
0.0851
0.0745
0.0421
0.0310
0.0571
0.0685
0.0637
0.0459
0.0582
0.0597
0.0676
0.0634
0.0829
0.0734
0.0649
B.wt.
0.0499
0.0688
0.0594
0.0408
0.0430
0.0571
0.0756
0.0503
0.0477
0.0509
0.0436
0.0726
0.0494
0.0557
0.0548
0.0490
0.0477
0.0480
0.0441
0.0605
0.0612
0.0618
0.0634
0.0632
0.0520
0.0581
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Research.
Cancer Research
394
.0900
FEMALES
0800
RA -wT -fu ORS-
~.
.0700
OVER 30 GRAMS 9
--
CONTROL RATS
.o6oo
e e
UNDER 3 0 GRAMS o
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120
140
160
180
200
220
BODY LENGTH [MM.)
FIo. 1.--Relation of relative liver weight to the body length in females.
Downloaded from cancerres.aacrjournals.org on June 17, 2017. © 1948 American Association for Cancer
Research.
Yeakel,----Liver Weight Increase in Rats with Tumors
.0900
395
D
MALES
9
9
.0800
.0700
--
:0600
-~
.o5oo
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OVER
30
GRAMS 9
,
UNDER
30
GRAMS o
9
CONTROL RATS
9
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9
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100
120
14.0
160
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180
200
2 20
BODY LENGTH CMM.)
FIG. L--Relation of relative liver weight to the body length in males.
Downloaded from cancerres.aacrjournals.org on June 17, 2017. © 1948 American Association for Cancer
Research.
396
Cancer Research
liver and the presence of a tumor in rats over 175
ram., although the effect on the liver was not apparent in smaller (younger) rats.
Constituents of the liver other than water may
influence the weight of this organ. Glycogen and
fat, as pointed out by Walter and Addis (3), represent passive reserve material, while an increase in
protein content, they believe, reflects work performed by the organ. In pregnancy (2, 3), the
weight of the liver as well as the percentage of
total body protein in it is increased. Addis and his
colleagues consider that this indicates a work hypertrophy, connected probably with protein anabolism. It is possible that similar work on the part
of the liver concomitant with the synthesis of neoplastic tissue may account for the increase in the
weight of the organ reported here. Moreover, the
failure to find an enlargement of the liver (compared with the controls) in smaller, younger rats
less than 180 ram. in body length may be explained
by the supposition that these animals were still
engaged in rapid body growth, so that their livers
w e r e already enlarged to the physiological maximum, and the additional stress imposed by a tumor
produced no demonstrable effect upon the liver
weight.
SUMMARY
1. The weight of tumor-free livers of male and
female Wistar albino rats with subcutaneous
growths (transplanted or primary) was compared
with the weight of the tumor.
2. Neither the observed weight of the liver, nor
its weight relative to the body weight (without the
growth) was correlated with the tumor weight.
3. The weight of the organ relative to body
length was significantly increased when the tumor
weighed over 30 gin. and when the body length of
the rat was over 175 mm.
4. Further growth of the tumor was not accompanied by a proportional increase in liver size.
5. The influence of a tumor on the weight of
the host's liver was more evident in female rats than
in males.
6. It is suggested that the enlargement of the
liver was connected with protein anabolism in t h e
growth of the tumor.
ACKNOWLEDGMENT
The author is deeply indebted to Dr. Margaret Reed
Lewis oi the Wistar Institute, Philadelphia, for the use of
her rats, and her advice and direction in this work; and
to Dr. Henry S. Simms, of the Department of Pathology,
College of Physicians and Surgeons, New York, for advice
in the preparation of the manuscript.
REFERENCES
1. McEw~, H. D., and HAVF~, F. L. The Effect of
Carcinosarcoma 256 on the Water Content of the
Liver. Cancer Research, 1:148-150. 1941.
2. Poo, L. J., LEw, W., LF~, D. D., and AVDIS,T. Protein
Anaboilsm in the Organs and Tissues of Pregnant
Rats at Different Levels of Protein Consumption. J.
Nutrition, 19:505-516. 1940.
3. WALTTm, F., and ADVIS, T. Organ Work and Organ
Weight. J. Exper. Med., 69:467-483. 1939.
4. YF~x~J~, E. H., and FARRm, E. J. Changes with Age
in the Weight of the Liver in Wistar Albino Rats.
Anat. Rec., 97:377-378 (Abstract). 1947.
.iLDICAL TECta,, ! Ak
Downloaded from cancerres.aacrjournals.org on June 17, 2017. © 1948 American Association for Cancer
Research.
Increased Weight of the Liver in Wistar Albino Rats with
Induced and Transplanted Tumors
Eleanor H. Yeakel
Cancer Res 1948;8:392-396.
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