A Single, Stimulatable Transport System in Rat Liver Shared by Certain Amino Acids Following Whole-Body γ-Irradiation

Abstract

Exposure of rats to whole-body .gamma.-irradiation stimulated hepatic transport of .alpha.-aminoisobutyric acid [AIB], N-methyl .alpha.-aminoisobutyric acid, cycloleucine, L-methionine and glycine by a common Na+-dependent transport system. This was demonstrated using reciprocal inhibition transport studies involving liver slices from normal and irradiated rats. The 5 amino acids studied were mutually inhibitory of each other''s transport in normal and irradiated animals. Although hepatic accumulation of L-phenylalanine was not stimulated by .gamma.-irradiation, it effectively inhibited stimulated transport of AIB, methionine, cycloleucine and glycine. In normal rats it inhibited Na+-dependent systems for AIB, cycloleucine and L-methionine to different degrees.