Helge J W, Bentley D, Schjerling P, Willer M, Gibala M J, Franch J, Tapia-Laliena M A, Daugaard J R, Andersen J L
Copenhagen Muscle Research Centre, Department Medical Physiology, Panum Institute building 12, University of Copenhagen, Blegdamsvej 3, 2200 N, Copenhagen, Denmark.
Eur J Appl Physiol. 2007 Sep;101(1):105-14. doi: 10.1007/s00421-007-0479-7. Epub 2007 May 26.
Fatty acid metabolism is influenced by training and diet with exercise training mediating this through activation of nuclear hormone receptor peroxisome proliferator-activated receptor alpha (PPARalpha) in skeletal muscle. This study investigated the effect of training and high fat or normal diet on PPARalpha expression in human skeletal muscle. Thirteen men trained one leg (T) four weeks (31.5 h in total), while the other leg (UT) served as control. During the 4 weeks six subjects consumed high fat (FAT) diet and seven subjects maintained a normal (CHO) diet. Biopsies were obtained from vastus lateralis muscle in both legs before and after training. After the biopsy, one-leg extension exercise was performed in random order with both legs 30 min at 95% of workload max. A training effect was evident as citrate synthase activity increased (P < 0.05) by 15% in the trained, but not the control leg in both groups. During exercise respiratory exchange ratio was lower in FAT (0.86 +/- 0.01, 0.83 +/- 0.01, mean +/- SEM) than CHO (0.96 +/- 0.02, 0.94 +/- 0.03) and in UT than T legs, respectively. The PPARalpha protein (144 +/- 44, 104 +/- 28, 79 +/- 15, 79 +/- 14, % of pre level) and PPARalpha mRNA (69 +/- [2, 2], 78 +/- [7, 6], 92 +/- [22, 18], 106 +/- [21, 18], % of pre level, geometric mean +/- SEM) expression remained unchanged by diet and training in FAT (UT, T) and CHO (UT, T), respectively. After the training and diet CS, HAD, PPARalpha, UCP2, UCP3 and mFABP mRNA content remained unchanged, whereas GLUT4 mRNA was lower in both groups and LDHA mRNA was lower (P < 0.05) only in FAT.
4 weeks one leg knee extensor training did not affect PPARalpha protein or mRNA expression. Furthermore, higher fat oxidation during exercise after fat rich diet was not accompanied by an increased PPARalpha protein or mRNA expression after 4 weeks.
脂肪酸代谢受训练和饮食的影响，运动训练通过激活骨骼肌中的核激素受体过氧化物酶体增殖物激活受体α（PPARα）来介导这一过程。本研究调查了训练以及高脂肪或正常饮食对人骨骼肌中PPARα表达的影响。13名男性对一条腿进行为期四周（总计31.5小时）的训练（T），而另一条腿（UT）作为对照。在这4周内，6名受试者食用高脂肪（FAT）饮食，7名受试者保持正常（CHO）饮食。在训练前后从双腿的股外侧肌获取活检样本。活检后，双腿以随机顺序进行单腿伸展运动，持续30分钟，强度为最大工作量的95%。训练效果明显，两组中训练腿的柠檬酸合酶活性增加了15%（P < 0.05），而对照腿未增加。运动期间，FAT组（0.86 +/- 0.01，0.83 +/- 0.01，均值 +/- 标准误）的呼吸交换率低于CHO组（0.96 +/- 0.02，0.94 +/- 0.03），UT腿低于T腿。FAT组（UT，T）和CHO组（UT，T）中，PPARα蛋白（相对于训练前水平的百分比分别为144 +/- 44，104 +/- 28，79 +/- 15，79 +/- 14）和PPARα mRNA（相对于训练前水平的百分比分别为69 +/- [2, 2]，78 +/- [7, 6]，92 +/- [22, 18]，106 +/- [21, 18]，几何均值 +/- 标准误）的表达分别不受饮食和训练的影响。训练和饮食后，两组中柠檬酸合酶（CS）、羟酰基辅酶A脱氢酶（HAD）、PPARα、解偶联蛋白2（UCP2）、解偶联蛋白3（UCP3）和肌肉脂肪酸结合蛋白（mFABP）的mRNA含量均未改变，而两组中葡萄糖转运蛋白4（GLUT4）的mRNA含量均降低，且仅在FAT组中乳酸脱氢酶A（LDHA）的mRNA含量降低（P < 0.05）。
为期4周的单腿伸膝训练不影响PPARα蛋白或mRNA的表达。此外，富含脂肪饮食后运动期间较高的脂肪氧化在4周后并未伴随PPARα蛋白或mRNA表达的增加。
