Effects of Methyl Testosterone on Thyroid Function, Thyroxine Metabolism, and Thyroxine-Binding Protein

Studies on the effect of androgenic steroids on thyroid function are difficult to evaluate because of a number of apparent discrepancies. Money, Kirschner, Kraintz, Merrill, and Rawson (1), using castrate rats on a low iodine diet, found that testosterone propionate had no influence on thyroid weight or on thyroid weight: body weight ratio, but did increase the radioiodine uptake. Kochakian and Evans (2) recently reported that this form of testosterone failed to influence the uptake or release of radioiodine by the thyroid of the castrate rat. Burris, Bogart, and Krueger (3), using heifers and young steers, found that testosterone propionate produced an increased gain in weight; furthermore, the thyroids of the treated animals weighed more, contained less colloid, and exhibited an increase in thyroid cell height. Voitkevich (4) is cited as stating that the goiters produced by propylthiouracil in guinea pigs and cocks are very considerably decreased by simultaneously administered methyl testosterone, and that propylthiouracil goiters are larger in castrate than -in normal cocks.