Thyroid Deiodinases

This episode explores how the body processes thyroxine to customize thyroid hormone action at the cellular level. We examine how the single circulating pool of prohormone follows one of two peripheral pathways to arrive at its final destination, diiodothyronine. By choosing whether outer-ring activation or inner-ring inactivation occurs first, type one, type two, and type three iodothyronine deiodinases grant individual tissues autonomous, tissue-specific metabolic control without disturbing systemic concentrations.