Tryptophan Metabolism via the Kynurenine Pathway in Experimental Chronic Renal Failure

BACKGROUND: Kidneys are involved in tryptophan (TRP) metabolism in two ways. They eliminate TRP derivatives on the one hand, and they produce several enzymes taking part in TRP metabolism mainly via the kynurenine pathway on the other. The aim of the present study was to examine the time-course of changes in the peripheral kynurenine products degradation during experimental chronic renal failure in rats. METHODS: Tryptophan, kynurenine, 3-hydroxykynurenine, kynurenic acid, xanthurenic acid, anthranilic acid and quinolinic acid were determined in plasma using high-performance liquid chromatography technique with UV, fluorescence and electrochemical detection. RESULTS: A decreased TRP level and significant increase in kynurenine pathway metabolite concentrations in plasma of uremic rats were found. CONCLUSIONS: Substantial disturbances in the peripheral kynurenic pathway were observed in experimental chronic renal failure. They may contribute to several symptoms of uremia.