EFFECT OF CORTICOTROPHIN ON THE CONTENT OF CORTICOTROPHIN IN THE PITUITARY GLANDS OF ADRENALECTOMIZED RATS

Abstract

The regulation of the rate of release of corticotropin from the anterior lobe of the pituitary gland has been ascribed to: (1) a humoral mechanism via the concentration of adrenocortical steroids in the body fluids or (2) a neurohumoral mechanism via the hypothalamus. The authors studied the effect of exogenous corticotropin on the corticotropin content of the pituitary gland since it has been shown that this content reflects the production and secretion rate. Adrenal-ectomized rats were used to eliminate the effect of exogenous corticotropin on the adrenocortical steroids and their resultant inhibitory effect on the pituitary gland. A daily dose of 2 IU of the agent for 2-3 weeks caused the content of corticotropin in the pituitary gland to be reduced about 50%. The dry weight of the gland decreased by at least 10%. The agent had, however, no effect on the body weight. No evidence either for or against the postulated mechanisms is therefore presented by this study.