Endothelin stimulates release of atrial natriuretic factor in anesthetized rats

The present study was designed to examine the effect of synthetic rat endothelin, a novel potent vasoconstrictor isolated from endothelial cells, on the release of immunoreactive atrial natriuretic factor (ir-ANF) in anesthetized rats. Systemic blood pressure and plasma ir-ANF concentration were measured at 1, 3, 5, 15, 30, and 60 minutes after rat endothelin administration (0.01, 0.10, 1.00 nmol/kg body weight [BW]). Administration of rat endothelin caused a long-lasting increase in mean blood pressure and produced a dose-dependent increase in plasma ir-ANF that peaked 5 minutes after the injection and remained higher than the basal value 60 minutes after the injection. These data suggest that administration of pharmacological doses of rat endothelin produces a profound release of ir-ANF into the circulation, which may cause vasodilation and diuresis to antagonize the effect of endothelin.