Renal effects of a novel endogenous natriuretic agent xanthurenic acid 8‐o‐β‐d‐glucoside in rats

Xanthurenic acid 8‐o‐β‐d‐glucoside is an endogenous derivative of tryptophan metabolism, isolated from urine of patients with chronic renal disease. This compound was suggested previously to act as a natriuretic hormone based on its ability to block short circuit currents in a frog skin assay and to induce a sustained natriuresis when injected into rats (C. D. Cain et al., Proc. Natl. Acad. Sci. USA 2007: 17873–17878). The present communication describes the effects of the compound on renal clearance and hemodynamic parameters in male Sprague–Dawley rats maintained on a normal salt (0.4–0.5%) diet. Intravenous administration of synthetic xanthurenic acid 8‐o‐β‐d‐glucoside in two consecutive incremental doses (6.3 and 31.5 nmol) resulted in a significant increase (P