Endocrine Abstracts

The thyroid hormones, L-thyroxine (T4) and 3,5,3'-triiodothyronine (T3), are essential for skeletal development and regulate bone mineralisation in the adult. T4 is a pro-hormone that is converted to active T3 by the type I and II 5'-iodothyronine deiodinase enzymes (D1 and D2). T4 and T3 are substrates for the type III 5-deiodinase enzyme (D3) which catalyses the irreversible production of inactive metabolites. The deiodinases are expressed widely in T3-target tissues and the...