Table 16. — Calcium determined microscopically in kidneys of fasted and nonfasted rats losing weight at 



different ages on SPE diet 





Fasted 



Nonfasted 



Weight loss and age of rats (days) 



Rats 



Kidney 

 calcium 



Rats with 



calcium in 



kidneys 



Rats 



Kidney 

 calcium 



Rats with 



calcium in 



kidneys 



Rats losing less than 100 grams: 

 Less than 300 - 



Number 



4 



12 



13 



8 



6 



/Score 











2 



! 6 







Percent 





 

 8 

 38 

 



Number 

 2 

 9 

 5 

 1 

 2 



1 



12 



15 



9 



5 



Score 







. 3 



. 6 



1.0 



1.5 



2. 

 3.0 

 2.0 

 2. 

 1.2 



Percent 







300 to 399 



33 



400 to 499. ... ... ._. 



40 



500 to 599. .. 



100 



600 and over . 



50 



Rats losing more than 100 grams: 

 Less than 300. 



100 



300 to 399... 



7 

 10 

 12 



7 



1. 4 

 1. 6 



.8 



.7 



57 

 60 

 50 

 43 



92 



400 to 499. . ... _ . 



93 



500 to 599. -. .. 



78 



600 and over. 



40 







showed evidence of calcium deposits; when weight 

 loss was more than 100 grams, the corresponding 

 percentages were 53 and 83. Calcium was found 

 most frequently and in the greatest amounts in the 

 kidneys of nonfasted rats 300 to 600 days of age 

 that had lost more than 100 grams. Although 

 fibrosis was not necessarily accompanied by 

 calcium, calcium was observed only in kidneys 

 showing extensive damage with evidence of 

 fibrosis. 



Rats fed SPM, SPB, and SPPB diets.— 

 In table 17 are summarized data from the micro- 

 scopic examination of kidneys and livers from 

 rats fed diets containing milk (SPM), beef (SPB), 

 or peanut butter (SPPB). The results for rats 

 that were maintaining weight did not differ mark- 



edly from those for rats that had lost less than 100 

 grams in weight before sacrifice, and the limited 

 data for these two groups of rats have been com- 

 bined. No separation by age was necessary 

 when weight loss exceeded 100 grams. 



In rats maintaining or losing less than 100 grams 

 in weight, the chief evidence of degenerative 

 changes in the kidneys was the presence of hyalin 

 casts. On all three diets, the kidneys of rats 

 under 300 days of age were generally normal in 

 appearance. On SPB diet, little evidence of 

 kidney damage was observed except in rats 500 

 days of age or older, whereas hyalin casts were a 

 frequent finding in the kidnevs of rats 300 to 

 500 days of age fed SPM or SPPB diets. 



When weight loss exceeded 100 grams, kidney 



Table 17 .—Kidney damage determined microscopically for rats maintaining or losing weight at different 



ages on SPM, SPB, and SPPB diets 



Weight loss, diet, and age of rats (days) 



Rats 



Average 

 age 



Histological rating of kidney 





Hyalin 



Cystic 



Glomerular 



Calcium 



Rats maintaining weight or losing less than 100 

 grams: 

 SPM: 



Less than 300 



Number 

 16 

 12 

 9 



16 



12 



8 



19 

 21 

 16 



14 

 15 

 13 



Days 



'.'17 

 353 

 577 



206 

 400 

 627 



217 



387 

 597 



624 

 556 

 512 



Score 

 0.4 

 .8 

 . 7 



. 1 



. 3 



1.2 



. 3 



1. 2 

 . 8 



1. 4 

 2.3 



2. 7 



Score 

 

 .3 

 .2 





 . 2 

 .5 



. 2 

 . 6 

 . 2 



1. 2 



2. 1 

 2. 5 



Score 

 

 . 2 

 . 2 



. 1 

 _ 2 

 ' 2 



. 1 

 . 6 

 . 1 



. 7 

 1.3 

 1. 1 



Score 

 



300to499._ _. _ .__ _ .. 







500 and over 







SPB: 



Less than 300 







300to499 _ .__ 







500 and over . 







SPPB: 



Less than 300 ... _ ... . 







300 to 499.. . 







500 and over 







Rats losing more than 100 grams: 



SPM 



. 6 



SPB 



1. 1 



SPPB 



. 5 







32 



