Abstract
Nine healthy women served as the subjects for the first to the fourth experiments. The effect of tryptophan deficiency on the metabolic products of tryptophan and niacin was examnied. Urinary nitrogen, riboflavin, anthranilic acid, xanthurenic acid and N1-methylnicotinamide, NAD and NADP in the blood were determined. When tryptophan was deprivated from the amino acid mixture for the nitrogen source, the excretion of total nitrogen, riboflavin, anthranilic acid and N1-methylnicotinamide was increased, but that of xanthurenic acid was decreased.
The ratio of NAD to NADP became lower. The difference of the effect between L-tryptophan and the D-isomer on the excretion of the metabolic products was not seen.
