Increased renal natriuretic peptide (urodilatin) excretion in heart failure patients

Accumulating evidence suggests that urodilatin, a kidney-derived member of the natriuretic peptide family, contributes as a major mediator of sodium excretion to body fluid regulation in healthy men. In contrast to other members of the natriuretic peptide family, pathophysiological data for the renal natriuretic peptide have still been missing. The present study compares renal synthesis of urodilatin in patients with congestive heart failure (CHF) and healthy volunteers. Because urodilatin excretion, considerably increases with increasing nutritive sodium intake (p<0.004), the CHF patients (15 NYHA I/II, 8 NYHA III/IV) were kept on a 165 mmol/day sodium diet and 6 healthy volunteers on a identical nutritive sodium intake level were selected as proper controls. Although urodilatin excretion significantly increased (p<0.027) with increasing severity of CHF and was therefore significantly higher in mild CHF (40.7 +/- 2.5 fmol/min) and severe CHF (54.7 +/- 6.6 fmol/min) than in healthy controls (3.2 +/- 4.2 fmol/min), both groups of CHF patients retained sodium and had significantly lower sodium excretion rates (NYHA I/II 79.0 +/- 6.9 micromol/min, NYHA III/IV 97.9 +/- 12.7 micromol/min) than the healthy controls (139 +/- 3.4 micromol/min). Our data suggest that renal urodilatin synthesis, may not be involved in the etiology of sodium retention in CHF, but may rather be stimulated to counteract antinatriuresis during CHF.