EPINEPHRINE OR NOREPINEPHRINE FAIL TO INFLUENCE PITUITARY-ADRENAL SECRETION IN MAN

It is unknown whether plasma catecholamines have direct physiologic ef fects on pituitary-adrenocortical secretion in man. Therefore we inves tigated the effects of epinephrine and norepinephrine on plasma concen trations of adrenocorticotropin (ACTH), beta-endorphin and cortisol, N ineteen healthy male volunteers received infusions of either NaCl, epi nephrine (0.10 mu g/kg/min) or norepinephrine (0.15 mu g/kg/min) for 2 0 minutes, 30 min before to 120 min after the infusion blood was conti nuously drawn to determine plasma levels of epinephrine, norepinephrin e, and cortisol. In addition, ACTH and beta-endorphin plasma concentra tions 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 psyc hological stress or exhausting physical exercise, However, these incre ases 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 i nfluence on pituitary-adrenal hormone concentrations.