EFFECT OF ENDOTHELIN-1 IN MAN - IMPACT ON BASAL AND ADRENOCORTICOTROPIN-STIMULATED CONCENTRATIONS OF ALDOSTERONE

The effect of exogenous endothelin-1 [2 pmol (5 ng)/kg . min for 15 mi n, followed by 1 pmol (2.5 ng)/kg . min for 105 min] on basal and ACTH (250 mu g, iv)-stimulated plasma concentrations of aldosterone, corti sol, testosterone, corticosterone, and 18-hydroxycorticosterone was in vestigated in a group of healthy male volunteers (n = 6). Plasma conce ntrations of aldosterone remained unchanged during a placebo experimen t (i.e. in the absence of both exogenous ACTH and of endothelin-1). In the absence of exogenous ACTH, the iv administration of endothelin-1 did not influence plasma concentrations of aldosterone. The iv adminis tration of 0.25 mg ACTH induced a rise in plasma concentrations of ald osterone from a basal value of 152.6 +/- 38.8 to 362.6 +/- 77.7 pmol/L . This ACTH-induced rise was markedly augmented (P < 0.01) by the conc omitant administration of endothelin-1, when peak plasma concentration s of aldosterone of 632.5 +/- 230.2 pmol/L were observed. Basal and AC TH-stimulated concentrations of cortisol, corticosterone, and 18-hydro xycorticosterone were unchanged by the concomitant infusion of endothe lin-1. Thus, exogenous endothelin-1 influences adrenal function in hea lthy men by selectively augmenting the ACTH-induced secretion of aldos terone.