Calorigenic effect of diiodothyronines in the rat
Calorigenic effect of diiodothyronines in the rat
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DOI：
10.1113/jphysiol.1996.sp021536
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发表时间：
1996-08-01
影响因子：
5.5
通讯作者：
Goglia, F
中科院分区：
文献类型：
--
作者：
Lanni, A;Moreno, M;Goglia, F
1.在甲状腺功能低下大鼠中，我们测定了不同剂量的3，3‘，5-三碘-L-甲状腺原氨酸(T-3)、3，3’-二碘-L-甲状腺原氨酸(3，3‘-T-2)和3，5-二碘-L-甲状腺原氨酸(3，5-T-2)对代谢非常活跃的组织的静息代谢(Rm)和氧化能力(以细胞色素氧化酶活性衡量)的影响。给甲状腺功能减退大鼠注射T-2异构体时，T-2异构体诱导出剂量依赖的生热效应。当Rm达到与正常甲状腺对照组(3，5-T-2和3，3‘-T-2分别为1.92+/-0.08和1.93+/-0.13(10-2)kg(-1)h(-1))无显著差异时，Rm的增加在2.5mug(100g身体重量)(-1)剂量下已经很明显，并在最高剂量10ug(100g身体重量)(-1)时观察到最大效果。与正常甲状腺对照组的2.1+/-0.12(10-2)kg(-1)h(-1)相比)。T-3给药使Rm恢复到正常甲状腺功能值，即使在2.5微克(100克体重)(-1)剂量下也是如此。T-2异构体对RM的影响与代谢非常活跃的组织(肝脏、骨骼肌、棕色脂肪组织(BAT)和心脏)的氧化能力增加是平行的。肝脏+3，3‘-T-2增加33%，肌肉+3，3’-T-2增加63%。相比之下，无论剂量如何，T-3对肝脏的影响最大，对骨骼肌的影响较小，但对心脏和蝙蝠的刺激作用不明显。这些结果提示T-2异构体可能是甲状腺激素直接调节能量代谢的中介。
1. In hypothyroid rats, we determined the effects of administration of different doses of 3,3',5-triiodo-L-thyronine (T-3), 3,3'-diiodo-L-thyronine (3,3'-T-2) and 3,5-diiodo-L-thyronine (3,5-T-2) ('T-2 isomers' refers specifically to these latter two isomers throughout this paper) on resting metabolism (RM) and on the oxidative capacity (measured as cytochrome oxidase activity) of tissues that are metabolically very active.2. The T-2 isomers induced a dose-dependent calorigenic effect when injected I.P. into hypothyroid rats. The increase in RM was already evident at a dose of 2.5 mu g (100 g body wt)(-1), and the greatest effect was observed at the highest dose, 10 mu g (100 g body wt)(-1) when RM reached a value not significantly different from that of the euthyroid controls (1.92 +/- 0.08 and 1.93 +/- 0.13 (1 O-2) kg(-1) h(-1) for 3,5-T-2 and 3,3'-T-2, respectively, vs. 2.1 +/- 0.12 (1 O-2) kg(-1) h(-1) for euthyroid controls). T-3 administration restored RM to normal euthyroid values, even at a dose of 2.5 mu g (100 g body wt)(-1).3. The effect of T-2 isomers on RM was paralleled by an increase in the oxidative capacity of tissues that are metabolically very active (liver, skeletal muscle, brown adipose tissue (BAT) and heart). The increases were between 33% (liver + 3,3'-T-2) and 63% (muscle + 3,3'-T-2). By contrast, T-3 induced its greatest effect on the liver, with a smaller effect on skeletal muscle, but no significant stimulation in heart and BAT, whatever the dose.4. These results suggest that T-2 isomers might be mediators of the direct thyroid hormone regulation of energy metabolism.