Köhrle J, Schomburg L, Drescher S, Fekete E, Bauer K
Klinische Forschergruppe der Medizinischen Poliklinik der Universität Würzburg, Germany.
Mol Cell Endocrinol. 1995 Feb 27;108(1-2):17-21. doi: 10.1016/0303-7207(95)92574-8.
The negative feedback control of thyrotropin production by the anterior pituitary involves local 5'-deiodination of L-thyroxine (L-T4) to the active thyroid hormone 3,3',5-triiodo-L-thyronine (T3) by two 5'-deiodinase isozymes which are distinctly regulated by thyroid hormone. T3 rapidly increased steady-state mRNA levels and activity of type I iodothyronine-5'-deiodinase (5'DI) in rat anterior pituitary and in reaggregate cultures of anterior pituitaries. Type II 5'-deiodinase activity determined in parallel with 3,3',5-triiodo-L-thyronine (rT3) as substrate was markedly lower than that of 5'DI. 5'DI mRNA levels and activity were higher in anterior pituitaries of female compared to male rats. Neither gender differences nor T3 stimulation of 5'DI activity were found in the posterior part. These data demonstrate a T3 dependent expression of 5'DI in euthyroid anterior pituitary and suggest that this isozyme serves a major function within the complex network of thyroid hormone homeostasis.
腺垂体促甲状腺激素产生的负反馈调控涉及两种5'-脱碘酶同工酶将L-甲状腺素（L-T4）局部5'-脱碘生成活性甲状腺激素3,3',5-三碘-L-甲状腺原氨酸（T3），这两种同工酶受甲状腺激素的显著调控。T3能迅速提高大鼠腺垂体及腺垂体再聚合培养物中I型碘甲腺原氨酸5'-脱碘酶（5'DI）的稳态mRNA水平和活性。以3,3',5-三碘-L-甲状腺原氨酸（rT3）为底物平行测定的II型5'-脱碘酶活性明显低于5'DI。与雄性大鼠相比，雌性大鼠腺垂体中的5'DI mRNA水平和活性更高。在垂体后部未发现性别差异以及T3对5'DI活性的刺激作用。这些数据表明在甲状腺功能正常的腺垂体中5'DI的表达依赖于T3，并提示该同工酶在甲状腺激素稳态的复杂网络中发挥主要作用。
