The Relative Effects of Pyridoxine Deficiency on Two Plasma Transaminases in the Growing and in the Adult Rat

Abstract

Rats, upon being fed diets deficient in pyridoxine for periods of two to 4 weeks, showed markedly depressed activity of two plasma transaminases. In young rats, the alanine enzyme was affected more markedly (85%) than the aspartic enzyme (63%). In adult rats, too, the alanine enzyme was more markedly depressed (60%) than the aspartic enzyme (22%) although the total effect was not as great as in the younger animals. Partial restoration of serum alanine transaminase enzyme activity was elicited by incubating the deficient serum with pyridoxal phosphate before adding the assay substrate. The activities of both the alanine and the aspartic enzymes of serum obtained from deficient rats were rapidly restored by (a) injecting the deficient rats with pyridoxine…HC1, or (b) by feeding the control diet to the deficient rats. The application of the use of these enzymes to the evaluation of the availability of vitamin B₆ in foods which were preserved by ionizing radiation was indicated.