had livers containing 24.9 and 28.3 percent fat. 

 The number of rats with damaged kidneys that 

 were maintaining their weight on this diet was 

 small, and more data are needed to establish the 

 possible significance of this relationship. 



On the stock diet, there was relatively small 

 variation in body weight, and data for rats weigh- 

 ing more than 600 grams were too limited to deter- 

 mine whether or not there was any relationship 

 between body weight and liver fat. 



On SPE diet, with high concentrations of fat 

 in the liver the usual finding, there was no evidence 

 that the percentage of fat in the liver was related 

 to body weight. A rat weighing 783 grams had a 

 liver containing 38.6 percent fat; one weighing 530 

 grams had a liver containing 51.2 percent fat. 



Rats losing weight on stock, SP 8 HVO, and 

 SPE diets. — In table 59 are summarized data for 

 rats that were losing weight on stock, SP 8 HVO, 

 and SPE diets. The results are reported for non- 

 fasted and fasted rats with further separation on 

 the basis of the extent of weight loss even though 

 the number of animals in some groups is small. 

 Most of the results with the stock diet were for 

 nonfasted rats and were similar to those observed 

 with animals maintaining weight on this diet. 

 When weight loss of nonfasted rats was less than 

 100 grams, the influence of glycogen on the per- 

 centage composition of the livers was apparent. 

 Regardless of the extent of weight loss of fasted 

 moribund rats fed SP 8 HVO diet, the composition 

 of the liver was similar to that obtained for fasted 

 rats that were maintaining weight. In nonfasted 

 rats fed this diet, livers tended to contain a higher 

 percentage of fat than in the fasted animals, but 

 again there was little evidence that extent of 

 weight loss influenced appreciably the composi- 

 tion of the livers. In contrast, the extent of weight 

 loss before sacrifice for rats fed SPE diet seemed 

 to influenced liver composition more than fasting. 

 The fatty livers characteristic of rats that 

 were maintaining weight on SPE diet were seen 

 in many of the moribund rats fed this diet, 

 although the percentage of fat was generally 

 somewhat lower than in rats maintaining weight. 

 When weight loss exceeded 100 grams, there was 

 a marked decrease in the number of rats with 

 liver fat exceeding 30 percent. 



The wide variation in liver fat of nonfasted rats 

 that were losing weight on SP 8 HVO diet did not 

 appear to be merely a reflection of reduced food 

 intake and extent of weight loss before sacrifice. 

 Low liver fat in these rats seemed to be associated 

 with excessively damaged kidneys, whether or not 

 there had been appreciable weight loss. Data for 

 liver fat and kidney damage are summarized in 

 table 60. In the first group are included values for 

 liver fat when kidney damage did not exceed a 

 rating of 2 for hyalin casts, with no glomerular or 

 cystic damage. In the second group are the 

 results for rats with kidneys showing cystic and 

 glomerular damage as well as hyalin. Of the 8 

 rats with kidneys showing little evidence of dam- 



age, 6 had livers containing more than 26 percent 

 fat; only 1 of the 7 rats with extensive kidney 

 damage had a liver containing more than 20 per- 

 cent fat (21.5 percent). A similar trend has 

 already been discussed for fasted SP 8 HVO rats 

 that were maintaining weight. On SPE diet, high 

 liver fats were found consistently in rats with 

 kidneys showing little or no kidney damage; the 

 highest fat was observed in a rat with small normal 

 kidneys. However, high liver fats were also ob- 

 tained frequently in rats with extensively damaged 

 kidneys, and no consistent relation between fat in 

 the liver and kidney damage was observed on 

 this diet. 



Rats maintaining weight on SPM, SPB, and 

 SPPB diets. — In table 61 are summarized the 

 more limited data for the composition of livers 

 from rats fed SPM, SPB, and SPPB diets. Data 

 are presented for two age groups: those 200 to 

 399 days, and those 400 to 599 days old. No 

 marked differences were observed in the composi- 

 tion of the livers of the young rats fed these three 

 diets, and the results are similar to those already 

 reported for comparable animals fed SP 8 HVO 

 diet. In the older rats, the percentage of fat in 

 the livers was higher and the percentage of protein 

 correspondingly lower than in 200- to 399-day-old 

 animals. Liver fat for rats fed SPB diet was 

 similar to that observed for comparable rats fed 

 SP 8 HVO diet. Higher liver fats were obtained, 

 however, for rats fed SPM or SPPB diets. The 

 percentage of ash in these livers was similar to 

 that found in the livers of SP 8 HVO rats, and no 

 differences with age were observed. 



The high liver fats for rats fed SPM and SPPB 

 diets appear to be related to their body weight. 

 Differences in body weight, however, do not 

 explain the results for rats fed SPB diet, as seen 

 in table 62. On the diet containing milk (SPM), 

 liver fat increased on the average from 16.9 for 

 rats weighing less than 500 grams to 29.7 for 

 those weighing 700 grams and more. A similar 

 trend was seen with rats fed the diet containing 

 peanut butter (SPPB). On beef (SPB), however, 

 only 3 of the 13 rats had livers containing more 

 than 20 percent fat, with one of the highest values 

 observed in a rat weighing 486 grams. 



Rats losing weight on SPM, SPB, and SPPB 

 diets. — No consistent trend with age was apparent 

 from the data on the composition of the livers 

 from rats that were losing weight on SPM, SPB, 

 or SPPB diets. Therefore, the data in table 63 

 are the results for all age groups combined. The 

 livers from these moribund rats showed differences 

 in composition that were similar to those from 

 rats that were maintaining weight. Liver fat was 

 consistently low for SPB rats, both fasted and 

 nonfasted. Liver fat tended to be high in SPM 

 rats, and again the high fat values seemed to be 

 related to the large number of heavy animals on 

 this diet. The highest liver fat with SPM diet 

 was 47 percent in a rat that lived to be 799 days 

 old and reached a maximum weight of 1,020 grams. 



71 



