Schrauwen-Hinderling V B, Hesselink M K C, Moonen-Kornips E, Schaart G, Kooi M E, Saris W H M, Schrauwen P
Department of Radiology, University Hospital Maastricht, Maastricht, The Netherlands.
Int J Sports Med. 2006 Oct;27(10):786-91. doi: 10.1055/s-2005-873020. Epub 2006 Feb 1.
Recently, we showed that short-term training induced a rapid increase in IMCL whilst insulin sensitivity tended to improve. Here we investigate molecular adaptations accompanying this physiological training-induced accumulation of IMCL. Nine untrained men (age: 23.3 +/- 3.2 y; maximal power output: 3.8 +/- 0.6 W/kg body weight) trained for two weeks. Before and after training, subjects cycled for three hours and biopsies were taken before and after exercise. mRNA concentrations of ACC2, HSL, LPL, Glut4 and HKII were quantified by RT-PCR and association of Glut4 with the membrane was quantified by immunohistochemical method. Endurance training resulted in a decrease of 29.1 % in ACC2 mRNA (p = 0.02). After training, ACC2 mRNA tended to decrease with acute exercise (- 24.4 % [p = 0.06]). HSL mRNA decreased with acute exercise after training (- 37.3 % [p = 0.002]). LPL mRNA concentrations increased with acute exercise before training (+ 42.4 % [p = 0.05]) and HKII mRNA increased with acute exercise before (+ 72.5 % [p = 0.025]) and after training (+ 99.3 % [p = 0.05]). After acute exercise, more Glut4 was associated with the membrane than before exercise, but it was not affected by training. We conclude that the training-induced increase in IMCL was accompanied by molecular adaptations in muscle to improve fat oxidative capacity, while markers of glucose metabolism were not yet changed. The present data are in line with the hypothesis that the fat oxidative capacity might be more important than the IMCL content in determining insulin sensitivity.
最近，我们发现短期训练可使细胞内线粒体甘油三酯（IMCL）迅速增加，同时胰岛素敏感性有改善趋势。在此，我们研究伴随这种生理训练诱导的IMCL积累的分子适应性变化。九名未经训练的男性（年龄：23.3±3.2岁；最大功率输出：3.8±0.6瓦/千克体重）进行了为期两周的训练。训练前后，受试者进行三小时的骑行运动，并在运动前后取肌肉活检样本。通过逆转录聚合酶链反应（RT-PCR）定量测定乙酰辅酶A羧化酶2（ACC2）、激素敏感脂肪酶（HSL）、脂蛋白脂肪酶（LPL）、葡萄糖转运蛋白4（Glut4）和己糖激酶II（HKII）的mRNA浓度，并用免疫组织化学方法定量测定Glut4与细胞膜的结合情况。耐力训练使ACC2 mRNA降低了29.1%（p = 0.02）。训练后，ACC2 mRNA在急性运动后有降低趋势（-24.4% [p = 0.06]）。训练后HSL mRNA在急性运动后降低（-37.3% [p = 0.002]）。训练前LPL mRNA浓度在急性运动后增加（+42.4% [p = 0.05]），HKII mRNA在训练前（+72.5% [p = 0.025]）和训练后（+99.3% [p = 0.05]）的急性运动后均增加。急性运动后，与运动前相比，更多的Glut4与细胞膜结合，但不受训练影响。我们得出结论，训练诱导的IMCL增加伴随着肌肉中的分子适应性变化，以提高脂肪氧化能力，而葡萄糖代谢标志物尚未改变。目前的数据符合以下假设：在决定胰岛素敏感性方面，脂肪氧化能力可能比IMCL含量更重要。
