Studies of tryptophan metabolism in protein-energy malnutrition (PEM).

Studies on tryptophan metabolism in PEM were performed. In this respect, the basal excretion of tryptophan and some of its metabolites, namely, kynurenine, 3 OH-anthranilic, anthramilic, indol-3-acetic, 5 OH-indol acetic and xanthurenic acids were determined. The response of these metabolites to oral tryptophan load, singly and in combination, with pyridoxine, were performed in kwashiorkor cases compared to normal controls. The study revealed that kynurenine leads to niacine pathway is hindered, Indole-3-acetic acid levels are lower and respond poorly to tryptophan loading in PEM. Increased levels of 5 OH-indol acetic were found in kwashiorkor compared to marasmus, although lower response to tryptophan was noted. Xanthurenic acid excretion is much higher in PEM and poorly responds to tryptophan load either singly or in combination with pyridoxine. These errors of tryptophan metabolism in PEM are suggested to be due to defects in the enzyme systems involved rather than to vitamin B6 deficiency.