Tryptophan metabolism in liver cirrhosis: Influence of oral antibiotics on neuropsychiatric symptoms.

Abstract

Oral tryptophan loading tests were performed on patients with cirrhosis of the liver before and after treatment with an oral antibiotic practically unabsorbed from the gastrointestinal tract. After antibiotic therapy, neuropsychiatric manifestations evoked by the oral administration of tryptophan were reduced in duration by about 50% and in severity as well despite a slightly enhanced elevation of serum total and free typtophan levels, compared to pretreatment loading tests, The urinary indican output also showed a significantly greater decrease in the post-treatment test (p <0.05) whereas no appreciable difference was observed in urinary 5-hydroxy-indoleacetic acid excretion between the pre-and post-treatment tests. The data suggest that neuropsychiatric manifestations seen following oral administration of tryptophan may be attributed to intestinal tryptophan metabolites rather than to this aromatic amino acid itself and /or its metabolites in the brain. tryptophan loading ; neuropsychiatric manifestation ; total and free tryptophan ; urinary indican ; urinary 5-hydroxy-indoleacetic acid