Table 15. — Kidney damage determined microscopically for rats losing weight at different ages on stock, 



SP 8 HVO, and SPE diets 



Weight loss, diet, 









Histological rating 







Kidneys with — 





and age of rats 



Rats 



Gross 

 damage 



















(days) 

























Hyalin 



Cystic 



Glomerular 



Calcium 



Hyalin 



Cystic 



Glomerular 



Calcium 



Rats losing less 























than 100 























grams : 























Stock: 



Number 



Score 



Score 



Score 



Score 



Score 



Percent 



Percent 



Percent 



Percent 



400 to 499 



1 







































500 to 599 



2 



_ 2 



. 5 















50 















600 to 699 



2 



1. 



1. 



. 5 











50 



50 











700 to 799 



4 



2. 2 



2. 



1. 



1.8 







75 



75 



75 







800 and over.. 



5 



2. 4 



1. 8 



1. 



1. 4 







100 



40 



60 







SP 8 HVO: 























Less than 300__ 



4 







































300 to 399 



2 







































400 to 499 



7 



.6 



.9 















57 















500 to 599 



5 



2. 3 



2. 



1. 



. 4 







80 



40 



40 







600 to 699 



6 



1. 4 



. 5 



2 



. 2 







33 



17 



17 







700 and over__ 



3 



. 7 



.3 



o' 











33 















SPE: 























Less than 300.. 



6 



. 3 



. 7 







. 2 







50 







17 







300 to 399 



21 



1.8 



1. 8 



. 9 



. 7 



. 1 



95 



29 



38 



14 



400 to 499 



18 



2. 7 



2. 2 



1. 8 



1. 2 



. 3 



94 



72 



72 



17 



500 to 599 



9 



3.8 



1. 9 



2. 6 



1.3 



. 7 



100 



89 



78 



44 



600 and over.. 



8 



3. 2 



2.5 



2.0 



1. 6 



. 4 



100 



88 



62 



12 



Rats losing more 























than 100 

















. 







grams : 























Stock: 























300 to 399 



2 



4. 



2.0 



2. 5 



3. 



1. 



100 



100 



100 



50 



400 to 499 



2 



3.5 



2. 5 



2. 5 



2. 







100 



100 



100 







500 to 599 



3 



3.3 



2.7 



3.0 



2. 7 







100 



100 



100 







600 to 699 



1 



4. 



4.0 



2. 



3. 







100 



100 



11)0 







700 to 799 



4 



2. 



2. 



. 8 



1. 5 







100 



50 



75 







800 and over.. 



2 



3.5 



2. 5 



2.0 



3. 







100 



100 



100 







SP8 HVO: 























Less than 300.. 



2 







. 5 















50 















300 to 399-.. 























400 to 499 



4 



3.5 



2. 5 



2. 8 



1.8 



1. 8 



100 



75 



75 



50 



500 to 599 



9 



2. 4 



2. 1 



1. 1 



1. 1 



1.2 



100 



56 



67 



44 



600 to 699 



7. 



2. 3 



2.0 



1. 9 



1.7 



. 6 



86 



71 



71 



43 



700 and over-. 



9 



3.0 



2. 3 



1.4 



1.3 



.3 



89 



67 



56 



22 



SPE: 























Less than 300.- 



1 



4. 



3.0 



1. 



1. 



2. 



100 



100 



100 



100 



300 to 399 



19 



3. 9 



2. 5 



3.2 



2. 



2. 4 



100 



95 



95 



79 



400 to 499 



23 



3.8 



2. 7 



3.0 



2. 1 



1. 9 



100 



100 



100 



74 



500 to 599 



21 



3.7 



2. 5 



3.3 



1. 9 



1.3 



100 



100 



95 



62 



600 and over.- 



12 



3.8 



2.3 



2. 9 



2. 1 



. 9 



100 



100 



92 



42 



grams in weight before sacrifice, the extent and 

 kind of damage found was similar to that already 

 seen (table 14) for rats that were fed this diet and 

 were maintaining or gaining weight. In the older 

 rats, however, there was an increase in the extent 

 of cystic or glomerular damage. When weight loss 

 exceeded 100 grams, no normal kidneys were seen 

 and more than 95 percent showed glomerular and 

 cystic damage as well as hyalin casts. Degenera- 

 tive changes were extensive regardless of age, and 

 the scores for cystic damage tended to exceed those 

 for glomerular damage, in contrast to the results 

 with rats fed the stock diet. Calcium was present 

 more frequently in the kidneys of rats fed SPE 

 diet than in those fed SP 8 HVO diet ; 1 8 percent of the 

 kidneys showed evidence of calcium deposition 



when weight loss was less than 100 grams; 62 

 percent, when the loss exceeded 100 grams. 



Data on SPE diet were sufficient to permit a 

 further evaluation of the factors influencing the 

 occurrence of calcium deposits in the kidneys. In 

 table 16, the results of microscopic examination for 

 calcium are considered in relation to age, weight 

 loss, and nutritional status of the rat at the time of 

 sacrifice. Calcium was found occasionally in the 

 kidneys of rats losing less than 100 grams and was 

 frequently found in the rats losing more than 100 

 grams. It was observed more often in kidneys 

 from nonf asted rats than in those from fasted rats, 

 regardless of weight loss. When weight loss was 

 under 100 grams, 9 percent of the kidneys from 

 fasted rats and 32 percent from nonfasted rats 



31 



