Tryptophan Metabolism in Human Subjects

Publisher Website
Google Scholar
Abstract
Tryptophan in the urine, plasma, and blood cells was determined for human subjects under different conditions of tryptophan intake. The concentration of tryptophan in the plasma and blood cells increased after the ingestion of crystalline l-tryptophan; at the maximum concentrations the amount of unbound tryptophan circulating in the plasma and cells in excess of that circulating immediately before ingestion of the dose was estimated to represent about 14 to 15% of the dose, regard-less of the size of dose. The amount of unbound tryptophan recovered in the urine in the 24 hours following the dose represented 0.5% or less of the dose. The data indicated that as the load filtered at the glomerulus was increased the amount of tryptophan that was reabsorbed by the renal tubules increased; the percentage reabsorbed remained practically the same for the different filtered loads.