Visser T J, Otten M H, Mol J A, Docter R, Hennemann G
Horm Metab Res Suppl. 1984;14:35-41.
The metabolism of 3,3',5'-triiodothyronine (rT3), 3,3'-5-triiodothyronine (T3) and 3,3'-diiodothyronine (3,3'-T2) by isolated rat hepatocytes in primary culture was studied by radioimmunoassay and by Sephadex LH-20 chromatography. The first step in the metabolism of rT3 is outer ring deiodination which is inhibited by thiouracil. In incubations with outer ring-labeled 3,3'-T2 or T3 the main products observed are iodide in the absence of thiouracil and the sulfate conjugates in the presence of the inhibitor. Rates of sulfation and iodide formation were both determined by the phenol sulfotransferase activity of the cells. Inner ring deiodination of T3 sulfate and subsequent outer ring deiodination of 3,3'-T2 sulfate by rat liver microsomes are much faster than the corresponding reactions for the non-conjugated iodothyronines. The results strongly suggest that sulfation precedes and in effect accelerates hepatic deiodination of T3 and 3,3'-T2.
通过放射免疫测定法和葡聚糖凝胶LH - 20色谱法，研究了原代培养的分离大鼠肝细胞对3,3',5'-三碘甲状腺原氨酸（反式T3）、3,3'-5-三碘甲状腺原氨酸（T3）和3,3'-二碘甲状腺原氨酸（3,3'-T2）的代谢。反式T3代谢的第一步是外环脱碘，这一过程受硫脲抑制。在用外环标记的3,3'-T2或T3进行孵育时，在无硫脲的情况下观察到的主要产物是碘化物，而在有抑制剂的情况下则是硫酸盐结合物。硫酸化速率和碘化物形成速率均由细胞的酚磺基转移酶活性决定。大鼠肝微粒体对T3硫酸盐的内环脱碘以及随后对3,3'-T2硫酸盐的外环脱碘，比非结合碘甲状腺原氨酸的相应反应要快得多。结果有力地表明，硫酸化先于并实际上加速了肝脏对T3和3,3'-T2的脱碘作用。
