Graded dose effects of angiotensin II on aldosterone production in man during various levels of potassium intake.

This study was performed to evaluate the hypothesis that adrenal aldosterone output is modulated by daily potassium intake in man. Eight normotensive subjects, aged 24-38 yr, were fed 3 separate 150 mEq sodium-containing diets. Potassium content ranged from 300 mEq daily during the first week, to 80 mEq daily and 10 mEq daily for the subsequent 2 wk. On days 4 and 5 of each diet each subject took oral dexamethasone 0.5 mg B.I.D. to prevent endogenous ACTH secretion. On day 6 an infusion of angiotension II (AII) was administered in doses of 0.1, 0.3, 1.0, 3.0 and 10.0 ng/kg/min, each lasting 30 min. Blood pressure, pulse, and plasma aldosterone and potassium were measured throughout the infusions. All at infusion rates of 3 and 10 ng/kg/min, produced significant increases in plasma aldosterone values during liberal potassium intake but not when potassium intake was 10 mEq/day. We conclude that dietary potassium in man modulates All-mediated aldosterone secretion.