Carbohydrate metabolism in its relation to the thyroid gland.—The effect of thyroid feeding on the glycogen-content of the liver and on the nitrogen distribution in the urine

Abstract

Our present knowledge of the relation of the thyroid gland to metabolism is based almost entirely on observations of the disturbances of metabolism produced by the diseases of the thyroid gland. By the application of physiological methods to patients suffering from graves' disease or from myxœdema an increase in the total metabolism and in the nitrogen metabolism in Graves' disease on the one hand, a decrease in the total metabolism in myxœdema on the other, have been definitely established. From these facts the conclusion has been drawn that the secretion of the thyroid gland increases the oxidative processes, so that an inadequate functioning of the gland brings about the condition of obesity and depressed nitrogen metabolism, characteristic of myxœdema. As regards the carbohydrate metabolism it has been observed clinically that in Graves' disease there is sometimes a tendency to alimentary glycosuria; the opposite condition—an increased tolerance for carbohydrates—has sometimes been found to occur in myxœdema. It is remarkable, however, that the attempts to verify these conclusions in the normal organism by producing experimentally a condition of excessive secretion of the gland—by means of feeding with thyroid gland,—or a condition of insufficient secretion of the gland—by extirpation of the thyroid gland—have on the whole not been successful. It is as yet not clear how the internal secretion of the thyroid gland produces its action on the metabolism. Nor do we know, at present, how the actions of this hormone on the different aspects of metabolism are related to one another.