High interindividual variability of indoxyl sulfate production identified by an oral tryptophan challenge test.

ABSTRACT: Indoxyl sulfate (IS) has been implicated in the pathogenesis of cardiovascular diseases. IS is converted from indole, a metabolite of dietary tryptophan through the action of gut microbial tryptophanase, by two hepatic enzymes: CYP2E1 and SULT1A1. We hypothesized that the effect of tryptophan intake on IS production might differ from person to person. We enrolled 72 healthy persons (33 ± 7 years; 54.2% women) to undergo an oral tryptophan challenge test (OTCT), in which 7 blood samples were collected at 0, 4, 8, 12, 24, 36, and 48 h following oral administration of L-tryptophan 2000 mg. We observed high interindividual variability of IS production in the response to an OTCT. Twenty-four subjects in the lowest tertile of the baseline-adjusted area under the curve of IS were defined as low-I

SUBMITTER: Lin TY 

PROVIDER: S-EPMC11730973 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature