Vascular and adrenocortical responses to a specific antagonist of angiotensin II.

Angiotensin II receptors in vascular smooth muscle and adrenal cortex have been characterized in the dog. The evidence was derived chiefly from experiments that assessed the ability of a structural analog of angiotensin II, [Sar1, Ile8] AII, to antagonize the effects of exogenously administered angiotensin II on arterial pressure and aldosterone secretion. [Sar1, Ile8] AII is a potent and specific blocker of the pressor response to angiotensinII; in the adrenal cortex, it is a much less effective inhibitor of aldosterone biosynthesis. These results indicate differences in the receptor sites for angiotensin II in vascular smooth muscle and adrenal cortex. Further, they raise the possibility that angiotensin II stimulates aldosterone secretion by mechanisms other than have already been proposed.