OBSERVATIONS ON CARBOHYDRATE METABOLISM FOLLOWING IRRADIATION OF THE PITUITARY LAND

Abstract

Various investigators have presented evidence to show that the hypophysis plays an important role in carbohydrate metabolism. Houssay (1) and his coworkers were the first to show that extracts of the anterior lobe of the hypophysis, when injected into normal dogs, produce hyperglycemia, glycosuria and ketonuria (2). Furthermore, these extracts, when given in high doses, inhibit dextrose utilization and a diabetic condition is produced. The ablation of the pituitary leads to hypersensitivity to insulin, hypoglycemia, convulsions during fasting, and an increase of dextrose tolerance (3, 4). All these findings have received adequate confirmation. In depancreatized dogs the removal of the hypophysis restores carbohydrate metabolism to an approximately normal condition but on the other hand renders the animal hypersensitive to insulin (5, 6). The injection of the anterior lobe extracts to the depancreatizedhypophysectomized animal causes a reappearance of the symptoms of diabetes. This subject has been reviewed in full by Houssay (7). Since the removal of the hypophysis decreases the symptoms of experimental diabetes, it has been advocated that destructive doses of roentgen ray to the hypophysis might produce similar results in clinical diabetes. Studies in carbohydrate metabolism, usually by simple dextrose tolerance curves in patients with diabetes mellirus before and after irradiation, have been made in the past by Selle, Westra and Johnson (8, 9), and Hutton (10). These investigators found little or no changes in dextrose tolerance after irradiation and there was no increased sensitivity to insulin.