Carbohydrate utilization by beef thyroid tissue.

Preliminary to a study of various pathological thyroid states, it was considered necessary to investigate first the carbohydrate metabolism of the normal gland. Also, it was thought that the information gained regarding the function and energetics of the normal gland might eventually provide an insight into the mechanism of formation of the hormone, thyroxine. Although numerous studies related to thyroid function have appeared in the literature, little is known of the pattern of carbohydrate utilization in this gland. Values for oxygen consumption (1) and the influence of goitrogenic and related compounds on the cytochrome oxidase activity of surviving thyroid slices (2) have been reported. That several enzyme systems involved in carbohydrate metabolism are present in the thyroid gland has been demonstrated by means of chemocytological procedures (3). Because of the important Ale of the thyroid gland in regulating the rate of cellular metabolism, considerable effort in the past has been spent in studying the effects of thyroxine separately and in conjunction with the thyrotropic hormone of the pituitary gland in biological oxidations. Within the large volume of data that have accumulated, varying results have been reported as to the capacity of thyroxine (4-9) and thyrotropic hormone (10-12) to exert a stimulative effect when added to isolated surviving tissues. It is the purpose of this investigation to study the carbohydrate metabolism of the normal thyroid gland and to reexamine the hormonal effect on respiration.