Reciprocal changes in atrial natriuretic factor and aldosterone during angiotensin converting enzyme inhibition in man

To investigate whether aldosterone responses to angiotensin Converting enzyme (ACE) inhibition are affected by changes in atrial natriuretic factor, which is known to inhibit aldosterone secretion, we measured blood pressure, plasma renin activity, aldosterone, atrial natriuretic factor and plasma potassium before and after 1 week of treatment with fosenopril, a long-acting ACE inhibitor, in eight normotensive subjects. Fosenopril caused a slight fall in blood pressure and increased plasma renin activity in all subjects. In contrast, aldosterone and atrial natriuretic factor were, on average, unchanged. However, for both these hormones a wide range of individual responses was observed (aldosterone from —254 to +240pmol/l, atrial natriuretic factor from +9.7 to — 16.6 pmol/l) and a significant inverse correlation was found between the changes in aldosterone and those in atrial natriuretic factor (r = —0.73, P <0.05). Plasma potassium was unchanged after the fosenopril treatment. These findings suggest an inter-relationship between atrial natriuretic factor and the aldosterone responses to short-term treatment with an ACE inhibitor.