Antihypertensive activity of bucumolol, a beta-adrenergic blocking agent, in spontaneously hypertensive rats

Effects of bucumolol, a beta-adrenergic blocking agent, on blood pressure and the renin angiotensin system were studied in spontaneously hypertensive rats (SHR). The results were compared with those of propranolol at an equipotent dose in beta-adrenergic blocking activity. Bucumolol lowered blood pressure and decreased plasma renin concentration (PRC) in both acute and long-term experiments. There was a significant correlation between percent changes in blood pressure and PRC following a single administration of bucumolol. Decrease in PRC persisted for the 6-week observation period despite the sustained reduction in blood pressure. On the other hand, propranolol did not lower blood pressure in acute experiment while it decreased renin release. These results suggest that inhibition of renin release is involved in the antihypertensive action of bucumolol.