METABOLIC RELATIONSHIP BETWEEN TRYPTOPHAN, VITAMIN B₆ AND NICOTINIC ACID IN RATS

Abstract

Experiments were carried out in regard to the effect of tryptophan and vitamin B₆ deficiency on tryptophan and niacin metabolites. Tryptophan-deficient rats promptly lost weight, and the administration of tryptophan to the diet resulted in a rapid gain in weight. Nitrogen loss was found in tryptophan-deficient rats, and nitrogen retention occurred when tryptophan was supplemented to the diet. There was no apparent effect of vitamin B₆ supplement on the excretion of nitrogen. The increase of urinary xanthurenic acid by vitamin B₆-deficient rats was seen when tryptophan was supplemented.
Vitamin B₆ had no effect on the excretion of niacin and N¹-methylnicotinamide (MNA) and N¹-methyl-2-pyridone-5-carboxiamide (pyridone).