EFFECTS OF AROTINOLOL, AN α- AND β-ADRENOCEPTOR ANTAGONIST, ON RENIN RELEASE FROM RAT KIDNEY CORTICAL SLICES

The effects of arotinolol on changes in renin release in rat kidney cortical slices in response to isoproterenol (IP) or norepinephrine (NE), were studied in comparison with those of AC-623, a main metabolite of arotinolol, and other typical adrenoceptor antagonists. Arotinolol, at concentrations of 10(-8) to 10(-4) mol/l, inhibited the increasing effect of 10(-6) mol/l IP on renin release, in a concentration-dependent manner. Similar results were observed with AC-623, propranolol or labetalol, although the inhibitory potencies of these agents were considerably lower than that of arotinolol. The blocking effect of arotinolol on the 10(-5) mol/l NE-induced decrease in renin release was much less potent than seen with other alpha-adrenoceptor blocking agents such as prazosin, phenoxybenzamine and labetalol. These data suggest that the potent blocking effects of arotinolol and its metabolite on the increased renin release in response to beta-adrenoceptor stimulation may contribute to the antihypertensive effect of this agent.