Corticosteroid-induced stimulation of atrial natriuretic peptide in man

Abstract

Abstract. Previously, we reported elevated plasma immunoreactive ANP (irANP) levels from the 2nd to the 9th day of administering either prednisone, 50 mg/day, or 9α-fludrocortisone acetate (9αF), 0.6 mg/day, to normal humans. To investigate the course of plasma irANP levels during the first 48 h of corticosteroid adminstration, 9 healthy men (mean age ± sem, 24 ± 1 years) received in randomised sequence A) a 4-h iv infusion of prednisolone sodium tetrahydrophthalate followed by oral administration of prednisone for 2 days; or B) a 4-h infusion of aldosterone followed by oral administration of 9αF for 2 days. Basal supine plasma irANP levels averaged 32 ± 5 ng/l in study A and 30 ± 6 ng/l in study B; they were unchanged or even deceased up to 24 h of glucocorticoid or mineralocorticoid administration, but rose (P < 0.01) to 56 ± 9 and 62 ± 12 ng/l at 48 h, respectively, of the two interventions. During glucocorticoid treatment, blood pressure (BP) and indices of the sodium-fluid volume state were unchanged after 48 h. During 9αF administration, body weight increased (1.1 ± 0.3%, P < 0.001), whereas urinary sodium excretion (63 ±7%, P < 0.001), hematocrit (4.1 ± 1.1%, P < 0.001), and plasma renin activity (38 ± 4%, P < 0.001) decreased. Conclusions: The increase in circulating irANP at 48 h of administration of either a glucocorticoid or a mineralocorticoid demonstrates a distinct but slow response of the ANP system to these corticosteroids in normal humans. ANP may play a potential role in mediating and/or modulating physiological and pathophysiological effects of corticosteroids.