Kiens B, Richter E A
Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark.
Am J Physiol. 1998 Aug;275(2):E332-7. doi: 10.1152/ajpendo.1998.275.2.E332.
The utilization of muscle triacylglycerols was studied during and after prolonged bicycle ergometer exercise to exhaustion in eight healthy young men. Two days before exercise and in the postexercise recovery period, subjects were fed a carbohydrate-rich diet (65-70% of energy from carbohydrates). Exercise decreased muscle glycogen concentrations from 533 +/- 18 to 108 +/- 10 mmol/kg dry wt, whereas muscle triacylglycerol concentrations were unaffected (49 +/- 5 before vs. 49 +/- 8 mmol/kg dry wt after exercise). During the first 18 h after exercise, muscle glycogen concentrations were restored to 409 +/- 20 mmol/kg dry wt. In contrast, muscle triacylglycerol concentrations decreased (P < 0.05) to a nadir of 38 +/- 5 mmol/kg dry wt, and muscle lipoprotein lipase activity increased by 72% compared with values before exercise. Pulmonary respiratory exchange ratio values of 0.80-0.82 indicated a relatively high fractional lipid combustion despite the high carbohydrate intake. From 18 to 42 h of recovery, muscle glycogen synthesis was slow and muscle triacylglycerol concentrations and lipoprotein lipase activity were restored to the preexercise values. It is concluded that muscle triacylglycerol concentrations are not diminished during exhaustive glycogen-depleting exercise. However, in the postexercise recovery period, muscle glycogen resynthesis has high metabolic priority, resulting in postexercise lipid combustion despite a high carbohydrate intake. It is suggested that muscle triacylglycerols, and probably very low density lipoprotein triacylglycerols, are important in providing fuel for muscle metabolism in the postexercise recovery period.
对8名健康年轻男性进行长时间自行车测力计运动直至力竭的过程中及运动后，研究了肌肉三酰甘油的利用情况。在运动前2天和运动后的恢复期间，受试者食用富含碳水化合物的饮食（碳水化合物提供65 - 70%的能量）。运动使肌肉糖原浓度从533±18降至108±10 mmol/kg干重，而肌肉三酰甘油浓度未受影响（运动前为49±5，运动后为49±8 mmol/kg干重）。运动后的前18小时内，肌肉糖原浓度恢复至409±20 mmol/kg干重。相比之下，肌肉三酰甘油浓度下降（P<0.05）至最低点38±5 mmol/kg干重，且肌肉脂蛋白脂肪酶活性较运动前增加了72%。尽管碳水化合物摄入量较高，但肺呼吸交换率值为0.80 - 0.82表明脂质燃烧比例相对较高。在恢复的18至42小时内，肌肉糖原合成缓慢，肌肉三酰甘油浓度和脂蛋白脂肪酶活性恢复至运动前水平。结论是，在使糖原耗竭的力竭运动过程中，肌肉三酰甘油浓度并未降低。然而，在运动后的恢复期间，肌肉糖原再合成具有较高的代谢优先级，尽管碳水化合物摄入量较高，但仍导致运动后脂质燃烧。提示肌肉三酰甘油，可能还有极低密度脂蛋白三酰甘油，在运动后恢复期间为肌肉代谢提供燃料方面很重要。
