SPECIFIC INHIBITION OF ALDOSTERONE RESPONSES TO ENDOGENOUS AND EXOGENOUS ANGIOTENSIN II BY SOMATOSTATIN

Aldosterone and renin responses to head-up tilt (60° for 1 h) and angiotensin II infusions (2, 5 and 10 ng/kg/min) 1 h later were compared in six normal subjects during infusions of somatostatin (3 ±g/kg/min) or saline. The infusions were performed on separate days two weeks apart. The increase in aldosterone due to exogenous angiotensin II and orthostasis were significantly attenuated by somatostatin. Neither the increase in plasma renin activity (PRA) nor the angiotensin II mediated suppression of PRA were affected by somatostatin. These findings are consistent with the recent observation that somatostatin suppresses aldosterone release in response to angiotensin II in rat adrenal cells in culture and they indicate a possible role for somatostatin in the regulation of aldosterone secretion.