Deiodinase and Brain Development

Abstract

Thyroid hormone receptors are enriched in neurons which are the primary target of T3 actions. Type 2 iodothyronine deiodinase (D2), which catalyzes conversion of thyroxine (T4) to 3,5,3′-triiodothyronine (T3), is expressed predominantly in glial cells, and type 3 iodothyronine deiodinase (D3), which catalyzes conversion of T4 to 3,3′,5′-triiodothyronine (rT3) and T3 to 3,3′-diiodothyronine (T2), is expressed in neurons. Thyroid hormone metabolism by D2 and D3 plays important roles in brain function and development.