Participation of prostaglandin and adrenergic nervous system in renin release induced by changes in renal arterial pressure in rats.

The response of plasma renin activity (PRA) to stepwise reductions in renal arterial pressure (RAP) induced by suprarenal aortic constriction (SAC) or hydralazine (0.1-30 mg/kg i.v.), and the effect of indomethacin (5 mg/kg i.v.) or propranolol (1.5 mg/kg) s.c.) on the PRA response were examined in anesthetized rats whose right kidneys had been removed 6-7 days earlier. The stepwise reduction of RAP by SAC or hydralazine produced a steep increase in PRA when RAP was below approximately 100 mm Hg. Above this level, PRA was unaffected by changes in RAP. The SAC-induced increase in PRA was nearly abolished by indomethacin. On the other hand, propranolol failed to affect the SAC-induced increase in PRA. The hydralazine-induced renin release was remarkably suppressed by either indomethacin Or propranolol. These results suggest that SAC-induced renin release is mainly dependent on the prostaglandin system, whereas hydralazine-induced renin release is dependent on the prostaglandin and the adrenergic nervous system. We estimated the threshold pressure for increasing renin release is approximately 100 mm Hg.