The Influence of Goitrogenic Compounds (Sulfonamides and Their Derivatives,thiourea and Its Derivatives) on Respiration of Thyroid Tissue¹

AN in vitro reaction in which appreciable amounts of radioactive iodine are incorporated into diiodotyrosine and thyroxine by surviving thyroid slices in as brief a period as 2 hours (Morton and Chaikoff, 1943) has provided a useful tool for elucidation of the mechanism of action of goitrogenic compounds, substances that produce an enlargement and hyperplasia of the thyroid gland. This procedure revealed that such compounds as the sulfonamides, p-aminobenzoic acid, thiourea, thiouracil, etc., inhibit the incorporation of inorganic iodide into diiodotyrosine and thyroxine (Franklin and Chaikoff, 1944; Franklin, Chaikoff, and Lerner 1944). In an earlier communication (Schachner, Franklin, and Chaikoff, 1943) it was shown that cyanide, azide, sulfide, and carbon monoxide inhibited the in vitro formation of diiodotyrosine and thyroxine from inorganic iodide by thyroid tissue. The inhibition produced by CO was more pronounced in the dark than in the light.