The aim of the present work was to investigate the energy metabolism and antioxidant status of rat liver mitochondria using a model of hyperthyroidism. In experimental animals, the level of triiodothyronine and thyroxine was increased 3- and 4-fold, respectively, in comparison with that in the control group, indicating the development of hyperthyroidism in these animals. Oxygen consumption was found to be higher in rats with experimentally induced hyperthyroidism (from 20 to 60% depending on the experimental scheme used), with a slight decrease in the efficiency of oxidative phosphorylation and respiratory state ratio. It was shown for the first time that the level the respiratory complexes of the electron transport chain in hyperthyroid rats increased; however, the quantity of complexes III and V changed unreliably. The assay of respiratory chain enzymes revealed that the activities of complexes I, II, and citrate synthase increased, whereas the activities complexes II+III, III, IV decreased in liver mitochondria of the experimental animals. Alterations in the oxidative state in liver mitochondria were found: a 60% increase in the hydrogen peroxide production rate and a 45% increase in lipid peroxidation. The activities of superoxide dismutase and catalase in the liver of experimental rats were higher than in the control. At the same time, the activity of glutathione peroxidase did not change. The data obtained indicate that the known activation of metabolism and changes in the oxidative status in thyrotoxicosis are associated with variations in the respiratory chain functioning and the antioxidant enzymes of mitochondria.

中文翻译：

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实验性甲状腺功能亢进症条件下大鼠肝线粒体的能量代谢和氧化状态

本工作的目的是使用甲亢模型研究大鼠肝线粒体的能量代谢和抗氧化状态。在实验动物中，与对照组相比，三碘甲状腺原氨酸和甲状腺素的水平分别增加了 3 倍和 4 倍，表明这些动物发生了甲状腺功能亢进症。发现实验诱导的甲状腺功能亢进大鼠的耗氧量较高（从 20% 到 60%，取决于所使用的实验方案），氧化磷酸化效率和呼吸状态比率略有下降。首次表明甲亢大鼠电子传递链呼吸复合物水平升高；然而，复合物 III 和 V 的数量发生了不可靠的变化。呼吸链酶检测显示，实验动物肝线粒体中复合物I、II和柠檬酸合酶活性升高，而复合物II+III、III、IV活性降低。发现肝线粒体氧化状态发生变化：过氧化氢产生率增加 60%，脂质过氧化增加 45%。实验大鼠肝脏中超氧化物歧化酶和过氧化氢酶的活性高于对照组。同时，谷胱甘肽过氧化物酶的活性没有变化。获得的数据表明，甲状腺毒症中已知的代谢激活和氧化状态的变化与呼吸链功能和线粒体抗氧化酶的变化有关。