The renal excretion of xanthurenic acid following L-tryptophan loading in depressed patients

✍ Scribed by M. Maes; M. De Ruyter; E. Suy

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: English
• Weight: 414 KB
• Volume: 2
• Category: Article
• ISSN: 0885-6222
• DOI: 10.1002/hup.470020406

✦ Synopsis

Xanthurenic acid (XA) is a secondary product of the biosynthesis of nicotinamide from L-tryptophan. Disturbances in this pathway have been observed in depression. An enhanced glucocorticoid secretion is considered to induce this pathway. This could result in reduced levels of L-tryptophan (L-TRP) in the plasma. The present study investigates whether the synthesis of X A from L-TRP is disturbed in depression, and also whether the synthesis of X A is intercorrelated with L-TRP or measures of glucocorticoid secretion. To this end the XA excretion in 24 hour urine following L-TRP loading was determined in 166 psychiatric inpatients. There were no significant differences in X A excretion between non-depressed psychiatric controls, minor depression and major depression. Among the depressed patients there was a significant (p < 0.01) negative correlation between the excretion of XA and total L-TRP levels in plasma, with abnormally decreased (p < 0.0006) L-TRP levels occurring in the depressed patients with a disturbed X A excretion (3 106.8 pmo1/24 hour).