The in vitro Deiodination of Thyroxine and Triiodothyronine

Abstract

Deiodination of ¹³¹I-T₃ and ¹³¹I-T₄ in the liver, kidney and spleen homogenates obtained from normal and thyroidectomized rats was studied before and after the administration of l-T₃ and l-T₄. Deiodination of ¹³¹I-T₃ in the liver and spleen homogenates was decelerated by the administration of l-T₃ or l-T₄ both in normal and thyroidectomized rats. Deiodination of ¹³¹I-T₃ and ¹³¹I-T₄ in kidney homogenates was accelerated by the administration of l-T₃ or l-T₄ both in normal and thyroidectomized rats. These results suggest that difference of metabolism between T₃ and T₄ would exist in thyroid disorders.