Abstract
An assay of corti-cotrophin-releasing principles is described, using rats with lesions in the median eminence of the hypothalamus, 18 hours after electro-coagulation. In vitro steroidogenesis by adrenal glands was used as a parameter of pituitary-adrenal activity. The blocking effect of the lesion on the release of ACTH (corticotrophin) in response to stress was measured by the effect of ether anaesthesia on corticoid production in vitro of the left adrenal, whereas steroidogenesis of the right adrenal was used as an index of the corticotrophic effect of corticotrophin-releasing principles.