THE EFFECT OF CORTISONE ON THE THYROIDAL AND RENAL METABOLISM OF IODINE

Abstract

Neither the basal level of the thyroid/plasma iodide concn. ratio found in hypophysectomized rats, nor the elevated level found in similar rats treated with TSH was affected by admn. of cortisone. Thyroidal clearance of plasma iodide in hypophysectomized rats given TSH is markedly increased over that found in animals not so treated. In niether group, however, was cortisone found to influence this parameter of thyroidal activity. Cortisone markedly increased the rate of disappearance of radioactive I from the plasma of hypophysectomized animals, regardless of whether or not they had been treated with TSH. The rapid decline in the plasma concn. of radioactive I, noted in animals treated with cortisone, could be entirely explained by an increase in the renal clearance of iodide which occurred following the admn. of this hormone, and was sufficient to explain a decrease in the total accumulation of I131 by the thyroid glands of animals so treated.