Bonen A, McCullagh K J, Putman C T, Hultman E, Jones N L, Heigenhauser G J
Department of Kinesiology, University of Waterloo, Ontario, Canada.
Am J Physiol. 1998 Jan;274(1):E102-7. doi: 10.1152/ajpendo.1998.274.1.E102.
We examined the effects of increasing a known lactate transporter protein, monocarboxylate transporter 1 (MCT1), on lactate extrusion from human skeletal muscle during exercise. Before and after short-term bicycle ergometry training [2 h/day, 7 days at 65% maximal oxygen consumption (VO2max)], subjects (n = 7) completed a continuous bicycle ergometer ride at 30% VO2max (15 min), 60% VO2max (15 min), and 75% VO2max (15 min). Muscle biopsy samples (vastus lateralis) and arterial and femoral venous blood samples were obtained before exercise and at the end of each workload. After 7 days of training the MCT1 content in muscle was increased (+18%; P < 0.05). The concentrations of both muscle lactate and femoral venous lactate were reduced during exercise (P < 0.05) that was performed after training. High correlations were observed between muscle lactate and venous lactate before training (r = 0.92, P < 0.05) and after training (r = 0.85, P < 0.05), but the slopes of the regression lines between these variables differed markedly. Before training, the slope was 0.12 +/- 0.01 mM lactate.mmol lactate-1.kg muscle dry wt-1, and this was increased by 33% after training to 0.18 +/- 0.02 mM lactate.mmol lactate-1.kg muscle dry wt-1. This indicated that after training the femoral venous lactate concentrations were increased for a given amount of muscle lactate. These results suggest that lactate extrusion from exercising muscles is increased after training, and this may be associated with the increase in skeletal muscle MCT1.
我们研究了增加已知的乳酸转运蛋白——单羧酸转运蛋白1（MCT1），对运动期间人体骨骼肌乳酸排出的影响。在进行短期自行车测力计训练前后[每天2小时，7天，运动强度为最大耗氧量（VO2max）的65%]，受试者（n = 7）以VO2max的30%（15分钟）、60%（15分钟）和75%（15分钟）完成连续的自行车测力计骑行。在运动前以及每个运动负荷结束时采集肌肉活检样本（股外侧肌）以及动脉和股静脉血样本。训练7天后，肌肉中的MCT1含量增加（+18%；P < 0.05）。训练后进行的运动期间，肌肉乳酸和股静脉乳酸的浓度均降低（P < 0.05）。训练前（r = 0.92，P < 0.05）和训练后（r = 0.85，P < 0.05），肌肉乳酸与静脉乳酸之间均观察到高度相关性，但这些变量之间回归线的斜率有显著差异。训练前，斜率为0.12±0.01 mM乳酸·mmol乳酸-1·kg肌肉干重-1，训练后增加了33%，达到0.18±0.02 mM乳酸·mmol乳酸-1·kg肌肉干重-1。这表明训练后，对于给定的肌肉乳酸量，股静脉乳酸浓度增加。这些结果表明，训练后运动肌肉的乳酸排出增加，这可能与骨骼肌MCT1的增加有关。
