Studies on the Effect of Tryptophan Deficiency on the Metabolic Products of Tryptophan and Niacin.

In 1906, Hopkins and Willcox reported that tryptophan was essential for animals nutrition. Since then, the effect of tryptophan deficiency upon animal nutrition has been discussed by many authors. Recently the interrelation between trypto phan and niacin metabolism was demonstrated. On the other hand, Kotake and his collaborators studied tryptophan metabolism, being especially interested in kynurenine. In 1950, Rose et al. (1) studied amino acid requirement of human adults, by using amino acid mixture. Their experiments made it possible to study the effect of the deprivation of each amino acid on the metabolism. In the pre sent experiment, the effect of the deprivation of tryptophan from amino acid mix ture on tryptophan and niacin metabolism was examined by observing the excre tion of their respective metabolic products in the urine and the trend of nicotin amide-adenine dinucleotide (NAD) and nicotinamide-adenine dinucleotide phosphate (NADP) in the blood.