Effect of pyridoxine-deficiency on the syntheses of aspartate aminotransferase in rat liver and muscle in vivo.

Abstract

The rates of synthesis of aspartate aminotransferase isozymes in the liver and skeletal muscle in pyridoxine-deficient rats were examined. The rates of synthesis were compared in rats given pyridoxine-deficient diet ad libitum, rats given control diet ad libitum and rats pair-fed with those on the deficient diet. The rates of incorporation of 3H-L-leucine by both cytosolic and mitochondrial enzymes were highest in pair-fed controls. Incorporation of radioactivity into the cytosolic enzyme was higher in deficient rat liver than in that of controls fed ad libitum, but the rate of incorporation into the mitochondrial enzyme was similar in these two groups. In muscle the rates of incorporation of labeled leucine into both isozymes were similar in all groups when expressed relative to total protein synthesis. It was suggested that increase of glucocorticoid receptor might result in increased synthesis of cytosolic aspartate aminotransferase in pyridoxine-deficient rat liver.