The effects of physiological doses of corticosteroid on catecholamine metabolism in man

Abstract

Eight psychiatric patients were divided into two groups; one group received a daily oral dose of 1 mg of the synthetic glucocorticoid dexamethasone for 29 days and the other received a placebo. Urine was collected for selected 24-hr periods and analyzed for epinephrine and norepinephrine. Plasma cortisol was also determined at prescribed days of the experiment. The results show that dexamethasone achieved a lowering of plasma cortisol values compared to the placebo treated group. Epinephrine excretion decreased progressively over the course of the experiment in steroid treated subjects, whereas no significant change was found in the control group. No differences were observed in norepinephrine output between the two experimental groups. The observed decrease in epinephrine output was attributed to a fall in the activity of the epinephrine-forming enzyme, phenylethanolamine N-methyl transferase, in the adrenal medulla, secondary to diminished adrenal corticoidogenesis resulting from the administered dose of dexamethasone. The present study shows that the administration of maintenance doses of glucocorticoids selectively reduced epinephrine levels while leaving unaffected norepinephrine excretion in man. This experimental procedure makes it feasible to investigate, in any one normal or emotionally disturbed individual, the consequences of reduced epinephrine levels on a variety of physiological and behavioral parameters during any given period.