Aldosterone and prolactin responsiveness after prolonged treatment of congestive heart failure with captopril

After long-term captopril treatment, an inappropriate increase in aldosterone levels has been observed in hypertensive patients. It is not known, whether a similar change would occur in patients with severe congestive heart failure, and whether it is due to a decrease in endogenous dopaminergic inhibition of aldosterone secretion or to aldosterone stimulation by ACTH or an ACTH-related peptide. Therefore, the aldosterone and prolactin responses to metoclopramide have been studied in 10 patients with severe congestive heart failure (NYHA Class III or IV) after 6 months of captopril treatment, before and 11 h after pretreatment with dexamethasone. 7 placebo-treated patients served as double-blind controls. In captopril-treated patients, the supine aldosterone levels exceeded the normal range and were as high as in placebo-treated patients. The responsiveness of aldosterone and prolactin to metoclopramide was not influenced by captopril. Only in the placebo group were the aldosterone levels decreased by dexamethasone. Captopril increased plasma renin activity and serum potassium, and decreased supine epinephrine and norepinephrine and serum sodium. Thus, previous reports of inappropriately high aldosterone levels after long-term captopril treatment were confirmed in patients with severe congestive heart failure. It is concluded that increased aldosterone is due neither to a decrease in endogenous dopaminergic inhibition nor to dexamethasone-suppressible stimulation of aldosterone secretion.