Abstract
That vitamins B and G play a unique and important rôle in the metabolism of proteins is believed by some investigators. Reader and Drummond 1 have stated that there is little hypertrophy of the kidneys of rats fed on diets rich both in protein and in vitamin B complex, and that the required vitamin B complex is quantitatively related to the amount of protein in the diet. As this conclusion was not in accord with certain of our own observations we planned experiments to test the thesis that renal enlargement produced by high protein diets is lessened by increased ingestion of vitamins B, G and the vitamin B complex.
Groups of 12 to 14 animals (30 days old), consisting of intact rats as well as those from which one kidney had been removed, were fed diets of 18 and 90% protein respectively for 56 days. The groups were fed 3 different levels of yeast and in addition the highest level of yeast was supplemented with (1) factor G, using auto-claved yeast or (2) factor B, in the form of tikitiki extract.† Additional experiments are in progress to test the effect of an excess of the heat-stable (vitamin G) and heat-labile (vitamin B) factors fed separately without yeast. At autopsy hearts and kidneys were weighed and renal enlargement calculated on the basis of the weights of these organs as published by Donaldson. 2
In the accompanying table are presented experimental data which show that: 1. Renal enlargement occurs in both nephrectomized and intact rats feci high protein diets. 2. This enlargement takes place irrespective of the amount of yeast consumed. 3. Supplementing yeast with additional vitamin G or vitamin B does not lessen the enlargement. 4. The consistent enlargement found does not indicate any quantitative relationship between the intake of protein and vitamins B and G in reducing renal hypertrophy as suggested by Reader and Drummond.
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