Activation and inactivation of thyroid hormone by type I iodothyronine deiodinase

FEBS Letters

Berry, Marla J.³  Visser, Theo J.⁴  Thoma, Rudy¹  Goglia, Fernando²  Harney, John W.³  Larsen, P.Reed³  Horst, Claus¹  Moreno, Maria⁴ 

[1] Marion Merrell Dow Research Institute, Henning Berlin R&D, D-12067 Berlin, Germany;Department of General and Environmental Physiology, University of Naples, I-80134 Naples, Italy;Thyroid Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA;Department of Internal Medicine III, Erasmus University Medical School, PO Box 1738, 3000 DR Rotterdam, The Netherlands

关键词: Thyroid hormone;    Iodothyronine;    Sulfate;    Deiodination;    Type I iodothyronine deiodinase;    Rat liver;    Transfection;    Human embryonic kidney (HEK) 293 cell;   

DOI  :  10.1016/0014-5793(94)00365-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The prohormone thyroxine (T4) is activated by outer ring deiodination (ORD) to 3,3′,5-triiodothyronine (T3) and both hormones are degraded by inner ring deiodination (IRD) to 3,3′,5′-triiodothyronine (rT3) and 3,3′-diiodothyronine, respectively. Indirect evidence suggests that the type I iodothyronine deiodinase (ID-I) in liver has both ORD and IRD activities, with preference for rT3 and sulfated iodothyronines as substrates. To establish this, we have compared the ORD of rT3 and IRD of T3 and T3 sulfate by homogenates of cells transfected with rat ID-I cDNA and by rat liver microsomes. In both preparations rT3 is the preferred substrate, while deiodination of T3 is markedly accelerated by its sulfation. Kinetic analysis provided similar K _m and V _max values in cell homogenates and liver microsomes. These data demonstrate unequivocally that ID-I is capable of both activating and inactivating thyroid hormone by ORD and IRD, respectively.

【 授权许可】

Unknown