Stimulation of net muscle protein synthesis by whey protein ingestion before and after exercise
Stimulation of net muscle protein synthesis by whey protein ingestion before and after exercise
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DOI：
10.1152/ajpendo.00166.2006
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发表时间：
2007-01-01
影响因子：
5.1
通讯作者：
Wolfe, Robert R.
中科院分区：
文献类型：
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作者：
Tipton, Kevin D.;Elliott, Tabatha A.;Wolfe, Robert R.
营养摄入的时机已被证明会影响运动后肌肉的合成代谢反应。先前，我们证明了在抗阻运动前而不是运动后摄入游离必需氨基酸和碳水化合物时，净氨基酸摄取更大。然而，目前尚不清楚运动前摄入全蛋白是否会比运动后产生更好的反应。本研究旨在检查肌肉蛋白平衡对乳清蛋白摄入的反应在阻力运动之前和之后。健康的志愿者被随机分为两组。在运动前（PRE, n = 8）或运动后（POST, n = 9）立即摄入乳清蛋白溶液。每位受试者进行10组，每组8次重复的腿部伸展运动。在股动静脉样本中测量苯丙氨酸浓度，以确定跨腿平衡。动脉氨基酸浓度升高了50%左右，在摄入蛋白质后，净氨基酸平衡从负向正转变。当从运动开始计算（PRE和POST分别为67 +/- 22和27 +/- 10）或从每次饮料的摄入（PRE和POST分别为60 +/- 17和63 +/- 15）时，PRE和POST之间的氨基酸摄取没有显著差异。因此，净肌肉蛋白质平衡对完整蛋白质摄入时间的反应不像游离氨基酸和碳水化合物的组合那样有反应。
Timing of nutrient ingestion has been demonstrated to influence the anabolic response of muscle following exercise. Previously, we demonstrated that net amino acid uptake was greater when free essential amino acids plus carbohydrates were ingested before resistance exercise rather than following exercise. However, it is unclear if ingestion of whole proteins before exercise would stimulate a superior response compared with following exercise. This study was designed to examine the response of muscle protein balance to ingestion of whey proteins both before and following resistance exercise. Healthy volunteers were randomly assigned to one of two groups. A solution of whey proteins was consumed either immediately before exercise ( PRE; n = 8) or immediately following exercise ( POST; n = 9). Each subject performed 10 sets of 8 repetitions of leg extension exercise. Phenylalanine concentrations were measured in femoral arteriovenous samples to determine balance across the leg. Arterial amino acid concentrations were elevated by similar to 50%, and net amino acid balance switched from negative to positive following ingestion of proteins at either time. Amino acid uptake was not significantly different between PRE and POST when calculated from the beginning of exercise ( 67 +/- 22 and 27 +/- 10 for PRE and POST, respectively) or from the ingestion of each drink ( 60 +/- 17 and 63 +/- 15 for PRE and POST, respectively). Thus the response of net muscle protein balance to timing of intact protein ingestion does not respond as does that of the combination of free amino acids and carbohydrate.