Effect of human alpha-atrial natriuretic polypeptide on adrenocortical function in man

To determine the effects of atrial natriuretic polypeptide (ANP) on plasma levels of ACTH, cortisol, aldosterone and dehydroepiandrosterone (DHEA), synthetic human alpha-ANP (h alpha-ANP) was infused i.v. into eight normotensive, disease-free volunteers, at a dose and duration previously found to be sufficient to produce apparent cardiovascular and renal effects. The mean basal concentration of plasma ACTH determined by radioimmunoassay was 18.2 +/- 3.1 ng/l. Plasma ACTH concentrations tended to be decreased during the infusion in all subjects. However, the change in plasma ACTH concentrations during infusion of h alpha-ANP was essentially the same as that during the infusion of saline. The mean plasma cortisol concentration was significantly suppressed from 25 to 40 min after the end of synthetic h alpha-ANP infusion. At 90 min after infusion, the mean plasma level of cortisol reverted to the pretreatment level. There was a non-significant increase in plasma renin activity following the infusion. The mean plasma aldosterone concentration was reduced by 15% (P less than 0.05) during the infusion and returned to preinfusion levels 10 min after termination of the infusion, after which the mean plasma concentration declined to the level seen during infusion. Administration of h alpha-ANP had no significant influence on plasma DHEA concentrations, but there was a tendency to decrease during the infusion. Our data suggest that synthetic h alpha-ANP inhibits adrenocortical steroidogenesis in man.