Epinephrine or norepinephrine fail to influence pituitary-adrenal secretion in man

Abstract

It is unknown whether plasma catecholamines have direct physiologic effects on pituitary-adrenocortical secretion in man. Therefore we investigated the effects of epinephrine and norepinephrine on plasma concentrations of adrenocorticotropin (ACTH), beta-endorphin and cortisol. Nineteen healthy male volunteers received infusions of either NaCl, epinephrine (0.10 micrograms/kg/min) or norepinephrine (0.15 micrograms/kg/min) for 20 minutes. 30 min before to 120 min after the infusion blood was continuously drawn to determine plasma levels of epinephrine, norepinephrine, and cortisol. In addition, ACTH and beta-endorphin plasma concentrations were analyzed at 6 time points before, during and after infusion. Infusion of catecholamines increased epinephrine and norepinephrine concentrations in physiological ranges as observed during intense psychological stress or exhausting physical exercise. However, these increases in catecholamine plasma levels neither affected concentrations of POMC-derived hormones nor plasma levels of cortisol. We conclude that in man, physiologic increases in circulating catecholamines have no influence on pituitary-adrenal hormone concentrations.