Selective Iodination Research Articles

COMPARATIVE ACTIVITY OF THIOURACIL AND OTHER ANTITHYROID COMPOUNDS IN THE RHESUS MONKEY

INTRODUCTION The selective iodine concentrating mechanism of the thyroid gland has been clearlydemonstrated to occur in two independent steps (Vander Laan and Vander Laan, 1947) (Taurog, Chaikoff and Feller, 1947). The first step which involves absorption of iodide ion from the blood is not inhibited by antithyroid agents of the thiouracil type and accounts for but a small portion of the total iodine present in the gland at any time. The second step involves the conversion of absorbed iodide into organically bound form, a considerable portion of which is of hormonal character (Wolff and Chaikoff, 1947). This mechanism accounts for the greater portion of accumulated iodine of the normal gland and is inhibited by thiouracil-like antithyroid drugs. On the basis of these considerations, McGinty and collaborators (1948) quantitated the activity of several antithyroid agents in rats and chicks following a single subcutaneous injection of the compounds in varying doses.