Köhrle J
Abteilung Molekulare Innere Medizin der Medizinischen Poliklinik der Universität Würzburg, Germany.
Cell Mol Life Sci. 2000 Dec;57(13-14):1853-63. doi: 10.1007/PL00000667.
Thyroid hormones control growth, development, differentiation and metabolism in vertebrates. Most of the actions of the active thyroid hormone T3 (3,5,3'-triiodo-L-thyronine) are exerted via ligand-activated nuclear T3 receptors. Activation of the secretory product of the thyroid gland, L-thyroxine (3,3',5,5'-tetraiodo-L-thyronine), or T4, is catalyzed by two enzymes, iodothyronine-5'-deiodinases type I and type II. Inactivation of T4 and T3 occurs via type III iodothyronine-5-deiodinase and to some extent by type I 5'deiodinase. Complementary DNAs (cDNAs) encoding the substrate-binding selenocysteine-containing subunits of the deiodinases were cloned, though some controversy still exists on the type II 5'-deiodinase subunits. Characterization of tissue-specific expression patterns indicates that these selenium-dependent enzymes exert tight control on local and systemic availability of active T3. Thus, deiodinases are envisaged as guardians to the gate of thyroid hormone action mediated by T3 receptors.
甲状腺激素控制脊椎动物的生长、发育、分化和新陈代谢。活性甲状腺激素T3（3,5,3'-三碘-L-甲状腺原氨酸）的大多数作用是通过配体激活的核T3受体发挥的。甲状腺分泌产物L-甲状腺素（3,3',5,5'-四碘-L-甲状腺原氨酸）或T4的激活由I型和II型碘甲状腺原氨酸5'-脱碘酶这两种酶催化。T4和T3的失活通过III型碘甲状腺原氨酸5'-脱碘酶发生，在一定程度上也由I型5'-脱碘酶介导。编码脱碘酶底物结合含硒半胱氨酸亚基的互补DNA（cDNA）已被克隆，尽管关于II型5'-脱碘酶亚基仍存在一些争议。组织特异性表达模式的表征表明，这些硒依赖性酶对活性T3的局部和全身可用性进行严格控制。因此，脱碘酶被视为T3受体介导的甲状腺激素作用之门的守护者。
