Sahlin K, Ekberg K, Cizinsky S
Department of Clinical Physiology, Huddinge University Hospital, Karolinska Institute, Huddinge, Sweden.
Acta Physiol Scand. 1991 Jun;142(2):275-81. doi: 10.1111/j.1748-1716.1991.tb09157.x.
Eight men cycled for about 6 minutes at workloads corresponding to 44 and 72% of maximal oxygen uptake and to fatigue at 98% maximal oxygen uptake. Blood samples from a brachial artery and a femoral vein were taken at rest and during exercise. Hypoxanthine, xanthine and urate in plasma were significantly elevated at fatigue and after 10 minutes of recovery. Only hypoxanthine showed a significant arterio-femoral venous difference. The release of hypoxanthine from the legs increased during the recovery period and was three-fold higher 10 minutes post exercise than at the end of exercise. It is concluded that the marked increase in plasma hypoxanthine which occurs during intensive exercise originates from the working muscle whereas the transformation to xanthine and urate may occur in other tissues. Glutathione, methemoglobin and malondialdehyd (MDA) were used as plasma markers of free radicals. Total glutathione (glutathione + glutathionedisulfide) in blood and plasma increased during intensive exercise and may be indicative of free radical formation. However, MDA was not detectable in plasma during any conditions (less than 0.1 mumol x l-1 plasma) and methemoglobin decreased slightly during exercise. Further studies using more specific techniques are required to determine whether the formation of free radicals is increased after brief intensive exercise.
八名男性以相当于最大摄氧量44%和72%的工作量骑行约6分钟，并以最大摄氧量98%的强度骑行至疲劳。在静息状态和运动过程中采集肱动脉和股静脉血样。血浆中的次黄嘌呤、黄嘌呤和尿酸盐在疲劳时及恢复10分钟后显著升高。只有次黄嘌呤表现出显著的股动脉-股静脉差异。腿部次黄嘌呤的释放量在恢复期增加，运动后10分钟比运动结束时高出三倍。研究得出结论，高强度运动期间血浆次黄嘌呤的显著增加源于运动的肌肉，而向黄嘌呤和尿酸盐的转化可能发生在其他组织中。谷胱甘肽、高铁血红蛋白和丙二醛（MDA）被用作血浆自由基标志物。高强度运动期间血液和血浆中的总谷胱甘肽（谷胱甘肽+谷胱甘肽二硫化物）增加，可能表明有自由基形成。然而，在任何情况下血浆中均未检测到MDA（血浆中低于0.1μmol·L-1），高铁血红蛋白在运动期间略有下降。需要使用更具体的技术进行进一步研究，以确定短暂高强度运动后自由基的形成是否增加。
