Metabolism of Tryptophan in Depressive Disease

Alan Frazer, Ghanshyam N. Pandey, Joe Mendels

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The metabolism of tryptophan (TRYP) to kynurenine and its metabolites, to tryptamine, and through serotonin to 5-hydroxyindoleacetic acid was studied in nine depressed patients and six non-depressed psychiatric subjects. In general, there were no significant differences in the basal urinary excretion of the nine metabolites measured between the two patient populations nor in the excretion of these metabolites after the administration of an oral dose of 2 gm of L-tryptophan. Also, pyridoxine (150 mg) did not differentially alter the TRYP-produced increases in urinary metabolites in the two groups of subjects. The data in this report do not support the suggestion of increased metabolism of TRYP along the kynurenine pathway in depression.

Original languageEnglish (US)
Pages (from-to)528-535
Number of pages8
JournalArchives of General Psychiatry
Issue number4
Publication statusPublished - Oct 1973


ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Psychiatry and Mental health

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