INFLUENCE OF OUABAIN ON THE FORMATION OF CORTICOSTERONE IN THE RAT ADRENAL GLAND

¹ Department of Pharmacology, College of Medicine, University of lllinois, Chicago, Illinois

The elaboration of corticosterone by adrenal tissue was measured after in vitro incubation of glands from rats treated with ouabain (0.75, 1.5 and 3.0 mg/kg) for 5, 15 and 30 days prior to the experiment. Steroid content was determined fluorometrically in medium and adrenal tissue. The response to trophic stimulation was also tested by the addition of adrenocorticotropin (ACTH) (0.1 U) to the medium in vitro. Chronic administration of ouabain induced histologic proliferation of the zona glomerulosa and significantly increased the weight of the adrenal gland. The data indicate that doses of ouabain of 1.5 mg/kg for 5 days, 3.0 mg/kg for 15 days and all doses after 30 days decreased the ability of the adrenal cortex to secrete corticosterone in the absence of trophic influence and markedly enhanced its ability to respond in the presence of ACTH, particularly after 15 days of drug administration at 1.5-and 3.0-mg/kg dosages.