Suppression of renin secretion in the rat kidney by a nonvascular alpha-adrenergic mechanism.

We studied the effect of alpha-adrenergic stimulation, using phenylephrine, on basal and isoproterenol-provoked renin secretion in the isolated perfused rat kidney. Infusion of phenylephrine increased renal perfusion pressure and prevented the response in renin secretion to isoproterenol. No suppression of basal secretion was observed. Renal vasoconstriction was abolished, and the response in renin secretion to isoproterenol was restored by alpha-adrenoceptor blockade with phenoxybenzamine. In contrast, when renal vasoconstriction was prevented by dihydralazine, suppression of renin release by phenylephrine still occurred. These observations support an inhibitory effect of a nonvascular alpha-adrenergic mechanism on renin release. We suggest that the alpha receptor mediating this effect is related directly to the juxtaglomerular cell.