STUDIES ON THE LOCI OF ACTION OF CORTICAL HORMONES IN INHIBITING THE RELEASE OF ADRENOCORTICOTROPHIN¹

Abstract

Compensatory adrenal hypertrophy is reduced in rats with diabetes insipidus as a result of hypothalamic lesions. Adrenal atrophy can be produced by injection of exogenous hydrocortisone into rats with diabetes insipidus. Rats with mild diabetes insipidus require less steroid to produce this effect than do normal rats, whereas rats with severe diabetes insipidus require more steroid than do normal rats. It is concluded that variations in cortical hormone concentration in the blood can still alter the release of ACTH in rats with diabetes insipidus though these rats may be. less sensitive to such alterations than normal rats. Administration of a large dose of hydrocortisone acetate to rats diminished the antidiuretic response to a standard mild electric shock stimulus and decreased the antidiuretic hormone titer in jugular venous plasma from stressed rats.