Permissive action of glucocorticoid substitution therapy on the effects of atrial natriuretic peptide (hANP) in patients with adrenocortical insufficiency.

To study the potential impact of glucocorticoids on the effects of human atrial natriuretic peptide (hANP) in man, the diuretic and natriuretic response to intravenous bolus doses of hANP (50 and 100 micrograms) was studied in seven male patients with deficient endogenous glucocorticoid synthesis, both during withdrawal of glucocorticoid therapy and during subsequent substitution with dexamethasone. Plasma concentrations of ACTH, though markedly suppressed by dexamethasone as compared to the unsubstituted state were not influenced by exogenous hANP either during deprival or substitution of glucocorticoids. Basal plasma concentrations of hANP were 10.3 +/- 8.4 pmol/l and 19.3 +/- 11.1 pmol/l during glucocorticoid withdrawal and following substitution with dexamethasone, respectively. When substituted with glucocorticoids, patients responded to hANP (100 micrograms) with an increase (p less than 0.025) in diuresis and sodium excretion, whereas no changes in diuresis and sodium excretion were seen following intravenous hANP during glucocorticoid withdrawal. These results suggest that glucocorticoids may have a permissive effect on hANP-mediated natriuresis and diuresis.