To determine the mechanism underlying altered adrenal responsiveness in patients with essential hypertension, the renin-angiotensin-aldosterone axis was assessed in normotensive and hypertensive subjects using three pharmacological probes: SQ 20881, a converting enzyme inhibitor; saralasin, a competitive angiotensin antagonist with prominent agonist properties; and angiotensin itself. All subjects were studied while supine and in balance on a 10 meq Na/100 meq K intake. The decrement in plasma aldosterone with SQ 20881 in 26 hypertensive subjects (15±3 ng/dl) was normal (13±4 ng/dl), suggesting that the altered adrenal responsiveness in hypertensives is not because of a change in a postreceptor event or in the relative contribution of angiotensin to the control of aldosterone secretion.
Gordon H. Williams, Norman K. Hollenberg, Thomas J. Moore, Stephen L. Swartz, Robert G. Dluhy