Inhibition of Insulin Degradation by Amino Acids and Related Compounds.

Abstract

In an in vitro system using insulin-I131 and a special liver preparation which degrades insulin, certain amino acids and related compounds were shown to inhibit insulin-I131 degradation, as measured by the accumulation of trichloracetic acid soluble radioactivity. Marked inhibition was shown with cystine, ergothioneine, 3, 4-dihydroxyphenylalanine, isoleucine, tryptophan, indole-3-acetic acid, and casein hydrolysate (Amigen). In the concentrations tested no significant inhibition was exerted by gluta-mine, glycine, beta-alanine, asparagine, arginine, serine, threonine, leucine, methionine, histidine, hydroxyproline or tyrosine.