Dependence of ratio of radioiodine concentrations in thyroid gland and serum on serum iodide concentration: with propylthiouracil.

Abstract

ASTUDY of the dependence of the ratio of the thyroid radioiodide concentration to the serum radioiodide concentration (T/S ratio) on the serum iodide concentration has been reported in the rat by Halmi (1954). This paper reports a similar study in normal and hypophysectomized mice. In addition, using simple models, formulae have been derived describing the dependence of the T/S ratio on the serum iodide concentration and predictions of the formulae are compared with the appropriate experimental results in both mice and rats. MATERIALS AND METHODS Male C3H mice were used. The normal mice were four months of age at the time of the radioiodine study. The hypophysectomized mice were fourteen weeks old at the time of the operation which was done eight days before the radioiodine study. They were hypophysectomized through the parapharyngeal approach. Completeness of the operation was ascertained by visual inspection of the region of the sella turcica for pituitaiy fragments using a binocular microscope at 9 × m...