Langer P, Suzuki M, Kakegawa T, Földes O, Gschwendtová K
Endocrinol Exp. 1985 Dec;19(4):253-60.
Bile was collected from cannulated bile duct under pentobarbiturate anesthesia and the excretion of several iodothyronines was estimated with the aid of radioimmunoassay as described previously. The excretion of triiodothyronine (T3) was significantly decreased between 4 and 6 h after a single injection of 20 and 40 mg kg-1 dexamethasone (DEX), while no changes in the excretion of thyroxine (T4) and reverse triiodothyronine (rT3) were found. In another experiment a decrease of T3 excretion was observed together with an increase of rT3 excretion and of T4/T3 and rT3/T3 ratio between 9 and 11 h after a single injection of 0.75, 1.5 and 3.0 mg kg-1 DEX, the differences being in most cases significant as compared to controls. In the same experiments a dose related increase of excretion of 3,3'-diiodothyronine (3,3'-T2) and 3,5-diiodothyronine (3,5-T2) was found, while the excretion of 3',5'-diiodothyronine (3',5'-T2) decreased with dose of DEX. Similar results were observed even after the administration of 1.5 and 3.0 mg kg-1 DEX for 5 days. In addition, the level of rT3 in serum was significantly increased at 9 h after a single dose of 3.0 mg kg-1 DEX and after 5 days administration of 1.5 and 3.0 mg kg-1 DEX. The data support a previous view that the changes in biliary excretion of iodothyronines are closely related to deiodinating metabolism of T4 in the liver and are expressed earlier and more remarkably than these in their plasma level.
在戊巴比妥麻醉下，通过插管胆管收集胆汁，并如前所述借助放射免疫分析法估计几种碘甲状腺原氨酸的排泄情况。单次注射20和40 mg/kg地塞米松（DEX）后4至6小时，三碘甲状腺原氨酸（T3）的排泄显著减少，而甲状腺素（T4）和反三碘甲状腺原氨酸（rT3）的排泄未发现变化。在另一项实验中，单次注射0.75、1.5和3.0 mg/kg DEX后9至11小时，观察到T3排泄减少，同时rT3排泄增加，T4/T3和rT3/T3比值增加，与对照组相比，大多数情况下差异显著。在同一实验中，发现3,3'-二碘甲状腺原氨酸（3,3'-T2）和3,5-二碘甲状腺原氨酸（3,5-T2）的排泄随剂量增加，而3',5'-二碘甲状腺原氨酸（3',5'-T2）的排泄随DEX剂量减少。即使给予1.5和3.0 mg/kg DEX 5天，也观察到类似结果。此外，单次给予3.0 mg/kg DEX后9小时以及给予1.5和3.0 mg/kg DEX 5天后，血清中rT3水平显著升高。这些数据支持了先前的观点，即碘甲状腺原氨酸胆汁排泄的变化与肝脏中T4的脱碘代谢密切相关，并且比血浆水平的变化更早、更显著地表现出来。
