Thiourea and Related Compounds in the Treatment of Hyperthyroidism *

The use of thyroid-depressant agents in the control of hyperthyroidism has raised questions concerning their relationship to other goitrogens and their mode of action. Other problems have been encountered as well, particularly with respect to toxic reactions, the effect of preliminary iodine administraton, and the control of the hypothyroid state which may result. The information available on these subjects has, therefore, been analyzed critically, and the relative merits of thyroidectomy and of medical treatment of hyperthyroidism are discussed. Types of goiter. More than a quarter of a century ago Marine and Kimball49 demonstrated that endemic goiter could be prevented by the administration of iodine. In the two decades prior to 1941 it was possible to assert that all nontoxic goiter was due to an insufficient supply of iodine. This statement was based on the observation that iodine counteracted the effects of all known goitrogenic diets. Thus, simultaneous administration of iodine prevented the development of goiters in animals fed winter cabbage'6 74, 576, 77 and in those fed soy-bean flour.70' 71, 78 Further investigation had proven that a number of pure organic cyanides and thiocyanates were goitrogenic,9' " 61 and that their action was also preventable by iodine.48 Since organic cyanides and cyanogens48 are regular constituents of winter cabbage and of soy-beans, it was concluded that these compounds were responsible for the goitrogenic action. Means,5' writing in 1936, asserted: "Thus cabbage goiter is cyanide goiter, and cyanide goiter is iodine-want goiter conditioned by an increased secretory demand placed upon the thyroid gland by a retarded tissue oxidation resulting from the action of hydrogen cyanide." In 1941 a type of goiter was discovered whose production could not be prevented by large doses of iodine. The goiter was produced by feeding Brassica seeds and rape seeds.32",' 3 These plants belong to the ca-bbage family, but the effects were not due to any cyanides which they might contain. The active agent was thought by Ken-