ADVANCEMENT OF KNOWLEDGE OF THE RôLE OF THE HYPOPHYSIS IN CARBOHYDRATE METABOLISM DURING THE LAST TWENTY-FIVE YEARS

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Abstract
Before 1929 the following facts were established: frequency of glycosuria and diabetes in acromegaly; capacity of post. lobe extracts to produce hyperglycemia and glycosuria; the antagonism between the action of insulin and post. lobe extract; the sensitivity of hypophysectomized animals to insulin; and the tolerance of hypophysectomized animals for different sugars. Until that time the role of the hypophysis was attributed exclusively to its post. lobe. In 1929 and 1930 the role of the ant. lobe of the hypophysis in the regulation of carbohydrate metabolism was proved, both in the normal and the diabetic states. The proof obtained in chronological order was the following: hypersensitivity to insulin of hypophysectomized animals is due to loss of the ant. and not the post. lobe; ant. hypophyseal extract increases resistance to insulin; hypophysectomized animals easily fall into hypoglycemia and lose their hepatic glycogen; this is prevented by giving ant. lobe extract; hypophysectomy or extirpation of the ant. lobe attenuates diabetes (pancreatic and phloridzinic); ant. lobe extract has a diabetogenic action. During injs. of ant. hypophyseal extract a diabetes is produced, firstly by extra pancreatic action; only after 2 or 3 days lesions in Langer-hans islets appear which cause a diminution of insulin secretion. If after some time injs. are interrupted a meta-hypophyseal diabetes is produced which is really a pancreatic diabetes due to irreversible pancreatic lesions. The hypophyseal diabetes in the dog and the cat is markedly different from that observed in the rat and the rabbit. In the first animals there is an excess of production of sugar from proteins while the consumption of glucose is not increased; in the rat and the rabbit the consumption of glucose is increased. In the action of hypophysis on carbohydrate metabolism and in pancreatic diabetes there are modifications of the function of the liver, the pancreas and peripheral tissues.