Effects of an angiotensin inhibitor on adrenocortical response to angiotensin II, ACTH, and K

A competitive inhibitor of angiotensin II has been studied in nephrectomized dogs treated with dexamethasone to suppress ACTH secretion. The inhibitor, [1-sarcosine, 8-alanine]angiotensin II (P113), has been shown by previous investigators to inhibit the pressor action of angiotensin II but not the pressor effect of other pressor agents. The present experiments demonstrate that P113 inhibits the stimulation of aldosterone secretion by angiotensin II but not by ACTH or potassium infusions. Therefore, P113 appears to be a specific inhibitor of angiotensin's action on both vascular and adrenocortical tissue. In this dog preparation, P113 has a mild nondose-related agonistic action on the blood pressure and a nonsignificant action on aldosterone secretion, although in some dogs P113 appears to have a definite agonist effect.