THE EFFECT OF THYROXIN ON THE RESPONSE OF THE THYROID GLAND TO THYROTROPIC HORMONE1

Abstract
The adm. of thyroxin to the immature o guinea pig depresses the response of the animal''s thyroid gland to exogenous thyrotrophic hormone as detd. by the mean cell height of the thyroid epithelium. The adm. of thyroxin to hypophysectomized o rate depresses the response of the animal''s thyroid gland to exogenous thyrotrophic hormone, as detd. by the mean cell height of the thyroid epithelium, as well as by the ability of the thyroid glands to take up radioactive iodine. The adm. of thyroxin to adult intact o rats depresses the mean cell height of the thyroid epithelium. By the adm. of an excess of thyrotrophic hormone, the cell height can be restored to normal.