Changes in Adrenal and Pituitary Concentrations of I 131 and P 32 Following Thyroidectomy. ∗

Abstract

Summary

1. Seventy days after thyroidectomy the ability of various organs of young and adult male albino rats to concentrate radioiodine I¹³¹ and radiophosphorus P³² was determined and compared to control animals. 2. The pituitary and adrenals of the young rats showed a markedly increased 3-hour concentration of I¹³¹ and a decreased 3-hour concentration of P³², significantly different from the control animals. 3. Mature animals exhibited an increased 3-hour concentration of I¹³¹ in the pituitary, with no significant differences in the 3-hour concentration of P³² from levels seen in the control animals. 4. The deleterious effects of thyroidectomy in the young animals with a high rate of tissue phosphate utilization was evidenced by the sharply decreased P³² concentration in the organs of those animals. Explanation for the markedly increased I¹³¹ concentrations in pituitary and adrenal of young and adult thyroidectomized animals is not readily apparent.