Local control of thyroid hormone action – role of type 2 deiodinase
- G Williams, Molecular Endocrinology Group, Imperial College London, London, W12 0NN, United Kingdom
- D Bassett, Metabolic Medicine, Imperial College London, London, W12 0NN, United Kingdom
- ↵Correspondence: Graham Williams, Email: graham.williams{at}imperial.ac.uk
Abstract
The thyroid gland predominantly secretes the pro-hormone thyroxine (T4) which is converted to the active hormone 3,5,3’-L-triiodothyronine (T3) in target cells. Conversion of T4 to T3 is catalyzed by the type 2 iodothyronine deiodinase enzyme (DIO2) and T3 action in target tissues is determined by DIO2-regulated local availability of T3 to its nuclear receptors, TRα and TRβ. Studies of Dio2 knockout mice have revealed new and important roles for the enzyme during development and in adulthood in diverse tissues including the cochlea, skeleton, brown fat, pituitary and hypothalamus. In this review we discuss the molecular mechanisms by which DIO2 controls intra-cellular T3 availability and action.
- Received 18 November 2010
- Received in final form 20 January 2011
- Accepted 3 February 2011
- Made available online as an Accepted Preprint 3 February 2011
- Accepted Preprint first posted online on 3 February 2011
