THE APPARENT PREPOTENT FUNCTION OF THE ADRENAL GLANDS

Abstract

The effects of adrenal-ectomy on carbohydrate metabolism are profound in character and appear to be primarily responsible for death of the animal. Blood glucose and liver glycogen are chiefly affected; these show marked reductions from the normal levels. There are also associated decreases in muscle glycogen, and increases in blood lactates. The glycogen of heart muscle is not reduced. In pancreatec-tomized and in hepatectomized animals, carbohydrate metabolism is affected no more critically than in cases of experimental adrenal insufficiency. The glycogenic and glycemic changes which occur after complete ad-renalectomy are not observed in cases of extirpation of the adrenal medulla alone. Administration of cortico-adrenal extract brings about recovery of animals which are in the terminal stages of insufficiency, apparently through initial restoration of normal carbohydrate values. Increments in circulating sugar to the normal or even to hyperglycemic levels occur early after extract injection and are invariably associated with the disappearance of insufficiency symptoms. There are also correlated and striking increases in liver glycogen. Restoration is completed with the re-establishment of muscle glycogen values and the diminution of blood lactic acid. None of the results are produced by the small amount of adrenalin (1:2,000,000) contained in the extract. Completely adrenalectomized animals show a markedly reduced ability to store liver glycogen. The evidence indicates that the cortico-adrenal tissues are primarily concerned in the maintenance of normal glucose and glycogen levels in the body. Since the cortex represents that part of the organ which is pre-eminently essential to life, the conclusion is derived that the regulation of carbohydrate metabolism may be considered as the pre-potent function of the adrenal glands.