Abstract
In a previous report 1 it was demonstrated that a severe pathological state characterized by hemorrhagic degeneration of the kidneys occurs within 10 days in young rats maintained on a low choline diet. This deficiency was prevented by choline. It was suggested that proteins relatively high in methionine and low in cystine possessed a choline-sparing action since the deficiency was produced more readily on diets containing fibrin than on those containing casein. Subsequent work has confirmed the earlier suggestion that choline might prevent the renal lesion resulting from the addition of cystine to a purified diet containing casein. Furthermore, it has been found that the addition of methionine to a diet containing fibrin completely protected the rats.
Normal kidneys were found in 40 g rats fed the following diet for 10 days: casein, 15; salt mixture, 4; calcium carbonate, 1; codliver oil, 5; lard, 35; agar, 2; sucrose, 32, and yeast, 6. Hemorrhagic kidneys invariably occurred if 0.3% cystine was added but not if 0.1% choline was added in addition to the cystine.
Hemorrhagic kidneys resulted if the protein of the above basal ration consisted of fibrin, 4; casein, 8, and dried egg white, 3. The addition of 0.04% choline or of 1% dl-methionine completely protected the rats.
The ratio of the 2 amino acids, methionine and cystine, is not the only factor which determines the choline requirement. This became evident from the fact that hemorrhagic lesions were produced on the 15% casein diet by decreasing the level of choline in the diet through substitution of vitamin concentrates for the codliver oil and yeast and through lowering the fat content to 10%. Furthermore, the effect of a fibrin diet in producing the renal lesions was no longer evident if the fibrin was decreased from 15 to 5%.
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