Medbø J I
National Institute of Occupational Health, Oslo, Norway.
Acta Physiol Scand. 1993 Sep;149(1):85-9. doi: 10.1111/j.1748-1716.1993.tb09595.x.
High-intensity exercise results in a large breakdown of glycogen. The glycogen lost may reappear as hexose phosphates, lactate, or it may be fully oxidized. Part of the lactate produced may be transferred from muscle to blood. There is, however, incomplete information on the relative importance of each endpoint of glycogen breakdown during high intensity exercise. Therefore, 16 healthy men cycled for between 30 s and 3 min until exhaustion. Muscle biopsies were taken from m. vastus lateralis before and immediately after exercise and analysed for glycogen, glucose, glucose-6-phosphate and lactate. In addition the blood lactate concentration was measured at exhaustion, and the O2 uptake was measured throughout the exercise for calculation of glycogen oxidation. The muscle glycogen concentration fell by 17-24 mmol kg-1 wet wt muscle, the muscle glucose and G-6-P concentrations rose by 1 and 4 mmol kg-1 respectively, and the muscle lactate concentration rose by 20-30 mmol kg-1. The blood lactate concentration at exhaustion was 4-9 mmol l-1 above pre-exercise value. Consequently, 60% of the glycogen lost reappeared as lactate within the working muscle, another 20-25% was found as other glycolytic intermediates, 4-13% of the glycogen loss could be accounted for by oxidation. Lactate released to blood could account for approximately 10% of all lactate produced. Therefore, when large muscles are heavily engaged, as during high intensity cycling, most of the glycogen broken down appears as lactate within the working muscle.
高强度运动导致糖原大量分解。分解产生的糖原可能以磷酸己糖、乳酸的形式重新出现，或者被完全氧化。产生的部分乳酸可能从肌肉转移至血液中。然而，关于高强度运动期间糖原分解各终产物的相对重要性，目前的信息并不完整。因此，16名健康男性进行了30秒至3分钟的自行车运动，直至精疲力竭。在运动前和运动结束后立即从股外侧肌取肌肉活检样本，分析其中糖原、葡萄糖、6-磷酸葡萄糖和乳酸的含量。此外，在运动结束时测量血乳酸浓度，并在整个运动过程中测量耗氧量，以计算糖原氧化量。肌肉糖原浓度下降了17 - 24 mmol·kg⁻¹湿重肌肉，肌肉葡萄糖和6-磷酸葡萄糖浓度分别上升了1 mmol·kg⁻¹和4 mmol·kg⁻¹，肌肉乳酸浓度上升了20 - 30 mmol·kg⁻¹。运动结束时血乳酸浓度比运动前值高出4 - 9 mmol·l⁻¹。因此，60%分解的糖原在工作肌肉中以乳酸的形式重新出现，另外20 - 25%以其他糖酵解中间产物的形式存在，4 - 13%的糖原分解可归因于氧化。释放到血液中的乳酸约占所有产生乳酸的10%。所以，当大肌肉如在高强度自行车运动中大量参与运动时，大部分分解的糖原在工作肌肉中以乳酸的形式出现。
