We investigated the effect of the fasting-induced reduction in triiodothyronine (T3) on metabolic changes that occur during fasting. In five obese women (T3 group) the serum T3 level during a 2200 kcal/day diet was 3.34 +/- 0.23 nmol/l while taking 20 micrograms T3 8-hourly, 0.65 +/- 0.04 after one week of fasting while not taking T3, and 2.9 +/- 0.3 after a second week of fasting while taking T3 20 micrograms 8-hourly. In three other obese women (control group) who did not take T3, T3 concentrations decreased during fasting and remained low at the end of both the first and second week of fasting. In the T3 group, resting metabolic rate (RMR) (O2 ml/min) decreased 11.7 percent at the end of one week of fasting, but then increased by 5.3 percent at the end of the second week of fasting, whereas in the control group RMR decreased by 13.1 percent after one week of fasting and a further fall of 13.3 percent occurred by the end of the second week of fasting. The RMR at the end of 2 weeks of fasting of the control group was significantly lower (P less than 0.05) than predicted using the equation of Dore, whereas that of the T3 group was as predicted using the same equation. The changes in leucine flux, leucine oxidation and non-oxidative portion of leucine flux were not different during fasting between the T3 group and the control group. Plasma concentrations of glucose, insulin and C-peptide increased from the end of one week of fasting to the end of 2 weeks of fasting in the T3 group, whereas they decreased in the control group. It is concluded that the changes in T3 concentration during fasting affected RMR, glucose metabolism and insulin secretion but failed to influence leucine metabolism.

中文翻译：

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三碘甲状腺素对肥胖妇女禁食两周期间亮氨酸动力学，代谢率，葡萄糖浓度和胰岛素分泌率的影响。

我们调查了禁食诱导的三碘甲状腺素（T3）减少对禁食期间发生的代谢变化的影响。在5名肥胖女性（T3组）中，每天2200 kcal饮食期间的血清T3水平为3.34 +/- 0.23 nmol / l，而每小时8小时服用20毫克T3，在禁食一周后不服用时为0.65 +/- 0.04 T3，并且在禁食第二周后为2.9 +/- 0.3，同时每小时8小时服用20毫克T3。在其他三位没有服用T3的肥胖妇女（对照组）中，T3的浓度在禁食期间下降，并且在禁食的第一周和第二周末均保持较低水平。在T3组中，禁食的静息代谢率（RMR）（O2 ml / min）在禁食1周结束时下降了11.7％，但在禁食第二周结束时又上升了5.3％，而在对照组中RMR降低了13。禁食一周后为1％，禁食第二周结束时进一步下降了13.3％。对照组禁食2周结束时的RMR显着低于使用Dore公式预测的（P小于0.05），而T3组的RMR则使用相同的方程预测。在T3组和对照组之间，在禁食期间，亮氨酸通量，亮氨酸氧化和亮氨酸通量的非氧化部分的变化没有差异。在T3组中，从禁食1周结束到禁食2周结束，血浆葡萄糖，胰岛素和C肽的浓度升高，而在对照组中，血浆浓度降低。结论是禁食期间T3浓度的变化影响RMR，