A study of tryptophan metabolism in man.

Tryptophan is one of the essential amino acids required by the mammalian body for protein anabolism. In recent years increasing interest has arisen in its intermediary metabolism. This is evidenced by the mass of literature which has appeared describing various aspects of its degradation. A number of pathways of tryptophan breakdown have been described and partially clarified, but only a portion of the total tryptophan intake by the mammalian body can be accounted for by the excretion of its known metabolites. Numerous studies have been made on variations in the urinary excretion of individual metabolites or on the appearance in the urine of metabolites detected in the urine of normal subjects