Maximum rate of oxygen uptake by human skeletal muscle in relation to maximal activities of enzymes in the Krebs cycle
Maximum rate of oxygen uptake by human skeletal muscle in relation to maximal activities of enzymes in the Krebs cycle
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DOI：
10.1111/j.1469-7793.1997.455bn.x
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发表时间：
1997-06-01
影响因子：
5.5
通讯作者：
Saltin, B
中科院分区：
文献类型：
--
作者：
Blomstrand, E;Radegran, G;Saltin, B
1. 10名受试者使用单腿的膝伸肌进行增量运动，直到他们的最大工作速率。测量腿部血流量和股动静脉氧差，以便能够计算腿部的摄氧量。从每位受试者髌骨到髂前下棘的21至25张计算机断层图像确定股四头肌的体积。3 .测定了三种酶在克雷布斯循环中的最大活性：柠檬酸合成酶、氧戊二酸脱氢酶和琥珀酸脱氢酶。在最大工作时，股四头肌的平均摄氧量为353 ml min(-1) kg(-1)，对应于克雷布斯循环速率为4.6 mu mol min(-1) g（-1）。这与氧戊二酸脱氢酶的最大活性(5.1 μ mol min（-1) g(-1)）相似，而琥珀酸脱氢酶和柠檬酸合成酶的活性平均分别为7.2和48.0 μ mol min(-1) g（-1）。提示，在这些酶中，只有氧戊二酸脱氢酶的最大活性才能提供氧化代谢能力的定量测量，并且该酶似乎在单腿膝关节伸展运动中以最大工作速率完全激活。
1. Ten subjects performed incremental exercise up to their maximum work rate with the knee extensors of one leg. Measurements of leg blood flow and femoral arteriovenous differences of oxygen were made in order to be able to calculate oxygen uptake of the leg.2. The volume of the quadriceps muscle was determined from twenty-one to twenty-five computer tomography section images taken from the patella to the anterior inferior iliac spine of each subject.3. The maximal activities of three enzymes in the Krebs cycle, citrate synthase, oxoglutarate dehydrogenase and succinate dehydrogenase, were measured in biopsy samples taken from the vastus lateralis muscle.4. The average rate of oxygen uptake over the quadriceps muscle at maximal work, 353 ml min(-1) kg(-1), corresponded to a Krebs cycle rate of 4.6 mu mol min(-1) g(-1). This was similar to the maximal activity of oxoglutarate dehydrogenase (5.1 mu mol min(-1) g(-1)), whereas the activities of succinate dehydrogenase and citrate synthase averaged 7.2 and 48.0 mu mol min(-1) g(-1), respectively.5. It is suggested that of these enzymes, only the maximum activity of oxoglutarate dehydrogenase can provide a quantitative measure of the capacity of oxidative metabolism, and it appears that the enzyme is fully activated during one-legged knee extension exercise at the maximal work rate.