HORMONAL FACTORS INFLUENCING CALORIGENESIS1

Abstract

IT IS well established that the thyroid is the gland controlling respiratory metabolism; that the thyroid in turn is controlled by a specific hormone of the anterior pituitary is equally well accepted. However, several reports have appeared which suggest that increase in metabolic rate can be obtained by pituitary extracts without thyroid mediation. Lactogenic hormone was reported to increase heat production in thyroidectomized as well as hypophysectomized birds (1). Growth hormone preparations were reported to increase the metabolic rate of thyroidectomized mammals (2, 3, 4). Evidence has been presented by Collip and his associates for a specific metabolic factor in anterior pituitary extracts other than thyrotrophic hormone (5, 6, 7). A calorigenic action from adrenocorticotrophic fractions has been reported by Astwood and others (8–14). Erythropoietically active pituitary fractions have been reported to restore the low metabolic rate of hypophysectomized and of thyroidectomized rats (15). A reexamination of the role of the pituitary and its target organs in calorigenesis was, therefore, in order.