GOITROGENIC AGENTS AND THYROIDAL IODINE: THEIR PHARMACODYNAMIC INTERPLAY UPON THYROID FUNCTION

¹ From the Department of Pharmacology, Yale University School of Medicine, New Haven, Conn.

When large doses of thiouracil are administered to rats, a persistent failure to trap iodine results. In part, this deficiency can be overcome by large doses of iodide. In this respect thiocyanate seems to differ from thiouracil both in the qualitative response and in the quantitative aspects of the dosages used. In the presence of either drug large doses of iodide will facilitate the storage of iodine; but conversion of iodide to diiodotyrosine (and incidentally to thyroxine) is prevented.

The synthesis of uniodinated thyroid protein and cellular hyperplasia can proceed unimpaired despite heavy dosage of thiouracil. Hyperplasia under thiocyanate, however, is nullified by iodide.