Abstract
Summary
Effects of dietary amino acids on tissue distribution of α-aminoisobutyrate (AIB) and of total ninhydrin-positive material have been examined in rats previously fed adequate or low amounts of protein. Intubation of casein hydrolysate or of glycine in rats receiving adequate protein increased the distribution ratio for AIB (the amount of amino acid in the tissue relative to that in plasma) in liver, whereas the ratios were decreased in rats receiving a low-protein diet. Ratios after feeding casein hydrolysate were generally decreased in skeletal muscle, heart and brain regardless of prior protein intake; glycine was without effect. Ratios were decreased by both glycine and casein hydrolysate in intestine and kidney. The relative distribution ratio (distribution ratio for ninhydrin-positive material/distribution ratio for AIB) was generally decreased by casein hydrolysate and glycine in all tissues but intestine and kidney. Glucagon altered this ratio only in liver. The results suggest that factors affecting distribution of AIB do not always alter distribution of total ninhydrin-positive material similarly.
This work was supported by the College of Agricultural and Life Sciences, University of Wisconsin-Madison and by USPHS NIH Grant AM10747. We are grateful to James L. Fleming for excellent technical assistance.
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