Scammell J G, Barney C C, Fregly M J
J Appl Physiol Respir Environ Exerc Physiol. 1981 Nov;51(5):1157-61. doi: 10.1152/jappl.1981.51.5.1157.
Groups of male rats were administered isoproterenol (ISO), thyroxine (T4), or both (ISO + T4) daily for 20 days in an attempt to mimic the effect of cold acclimation on the rate of outer-ring deiodination of T4 to triiodothyronine (T3) by 2,000-g supernatants of homogenates of liver and kidney. The rates of hepatic and renal deiodination of T4 to T3 in an additional group of rats exposed to 4 +/- 1 degree C for 20 days were 53 and 71% higher, respectively, than control. Administration of ISO (100 micrograms . kg-1 . day-1) did not affect the rate of deiodination of T4 to T3 by either hepatic or renal tissue. Administration of T4 (50 micrograms . kg-1 . day-1) resulted in rates of hepatic and renal deiodination of T4 that were 297 and 222% higher, respectively, than control. Administration of ISO + T4 resulted in a rate of conversion of T4 to T3 not significantly different from that observed when T4 was administered alone. Serum concentration of T4 was elevated after administration of both T4 and ISO + T4, whereas serum concentration of T3 was elevated significantly above that of control only in the cold-acclimated group. These results suggest that the increased rate of 5'-monodeiodination of T4 by hepatic and renal homogenates from cold-acclimated rats is not a result of increased beta-adrenergic activity but can be accounted for by the increase in thyroid activity observed in these animals.
为了模拟冷适应对肝脏和肾脏匀浆2000克上清液中甲状腺素（T4）外环脱碘生成三碘甲状腺原氨酸（T3）速率的影响，将雄性大鼠分组，每天给予异丙肾上腺素（ISO）、甲状腺素（T4）或两者（ISO + T4），持续20天。另一组暴露于4±1摄氏度20天的大鼠，其肝脏和肾脏中T4脱碘生成T3的速率分别比对照组高53%和71%。给予ISO（100微克·千克⁻¹·天⁻¹）对肝脏或肾脏组织中T4脱碘生成T3的速率没有影响。给予T4（50微克·千克⁻¹·天⁻¹）导致肝脏和肾脏中T4脱碘的速率分别比对照组高297%和222%。给予ISO + T4导致T4向T3的转化率与单独给予T4时观察到的转化率没有显著差异。给予T4和ISO + T4后，血清T4浓度升高，而仅在冷适应组中血清T3浓度显著高于对照组。这些结果表明，冷适应大鼠肝脏和肾脏匀浆中T4的5'-单脱碘速率增加不是β-肾上腺素能活性增加的结果，而是这些动物中观察到的甲状腺活性增加所致。
