Response in Myocytes and Change in Antioxidants Induced by Oxidative Stress

1)健康受试者在最大摄氧量（VO_<max>）运动时血清泛醇- lo （uqh_2 - 10，一种还原形式的泛醇- lo）水平在自行车测力仪上的变化。在运动后，VO_<max>时血清乳酸水平比运动前高5倍。血清抗氧化剂中，VO_<max>时uqh_2 - 10与总uq - 10之比（uqh_2 - 10 /总uq - 10 (uqh_2 - 10 + uq - 10)）显著低于运动前。在VO_<max>时，血清抗坏血酸水平比运动前高1.2倍，而α -生育酚水平不高。本研究表明，在VO_<max>的自行车测力仪上进行有氧运动后，血清中uqh_2 - 10和抗坏血酸的水平发生了变化，并表明这些抗氧化剂可能对消除运动产生的氧自由基有有益的作用。2) γ -谷氨酰半胱氨酸乙基酯对缺硒大鼠心脏功能障碍的保护作用硒（Se）缺乏导致62%的心电图异常发生率，左心室dP/dt降低63%，硫代巴比妥酸反应物质（TBARS）升高。γ -谷氨酰半胱氨酸乙基酯（γ - gce）（一种膜渗透性谷胱甘肽前体）增加细胞内谷胱甘肽浓度（[GSH]i），防止心功能障碍和TBARS增加。缺硒大鼠心脏匀浆中GSH（硒依赖性GSH过氧化物酶（Se-Gpx））活性的V*值为正常大鼠心脏匀浆的三分之一，而K_m值为三分之一。虽然γ -GCE不影响Se-Gpx V_<max>和K_m， forGSH，但它确实诱导了[GSH]_i的显著增加。这些数据表明[GSH]_i的增加可能在预防缺硒大鼠TBARS增加和心功能障碍中起作用。

1)Decreased serum ubiquinol-lO levels in healthy subjects during exercise at maximal oxygen uptakeWe studied the changes of serum ubiquinol-lO (UQH_2-1O, a reduced form of ubiquinone) levels during exercise on a bicycle ergometer at maximal oxygen uptake (VO_<max>) In response to the exercise, serum level of lactate at VO_<max> was S times higher than that before the exercise. Among serum antioxidants, the ratio of the UQH_2-1O to the total UQ-1O (UQH_2-1O/total UQ-1O (UQH_2-1O + UQ-1O)) at VO_<max> was significantly lower than that before the exercise. Serum levels of ascorbate but not alpha-tocopherol at VO_<max> were 1.2 times higher than those before the exercise.This study demonstrated that in the response to aerobic exercise on a bicycle ergometer at VO_<max>, serum levels of UQH_2-1O and ascorbate changed, and also showed that such antioxidants may play beneficial role for the elimination of exercise-derived oxygen radicals.2)Protective effect of gamma-glutamylcysteinylethyl ester on dysfunction of the selenium-deficient rat heartSelenium (Se) deficiency induced a 62% incidence of electrocardiographic abnormalities, a 63% reduction in dP/dt in the left ventricle, and an increase in thiobarbituric acid reacting substances (TBARS). Administration of gamma-glutamylcysteinylethyl ester (gamma-GCE)(a membrane-permeating GSH precursor) increased the intracellular GSH concentration ([GSH]i) and prevented the cardiac dysfunction and the TBARS increment. The V*, but not the K_m, for GSH of Se-dependent GSH peroxidase (Se-Gpx) activity in Se-deficient rat heart homogenates was one-third that of normal rat heart homogenates. Although gamma -GCE did not affect the Se-Gpx V_<max> and K_m, forGSH, it did induce a substantial and significant increase in [GSH]_i.These data suggest that the increase in [GSH]_i may have played a role in preventing the TBARS increase and cardiac dysfunction in Se-deficient rats.