Branched-Chain Amino Acid Ingestion Stimulates Muscle Myofibrillar Protein Synthesis following Resistance Exercise in Humans.
Branched-Chain Amino Acid Ingestion Stimulates Muscle Myofibrillar Protein Synthesis following Resistance Exercise in Humans.
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DOI：
10.3389/fphys.2017.00390
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发表时间：
2017
影响因子：
4
通讯作者：
Tipton KD
中科院分区：
文献类型：
--
作者：
Jackman SR;Witard OC;Philp A;Wallis GA;Baar K;Tipton KD
摄入完整的蛋白质或必需氨基酸（EAA）刺激雷帕霉素复合物-1（mTORC 1）信号传导的机制靶点和抗阻运动后的肌肉蛋白质合成（MPS）。本研究的目的是研究肌原纤维-MPS对仅摄入支链氨基酸（BCAA）（即，不同时摄入其它EAA、完整蛋白质或其它大量营养素）。十名接受过阻力训练的年轻男性（20.1 ± 1.3岁）完成了两项试验，在阻力运动后立即摄入5.6 g BCAA或安慰剂（PLA）饮料。肌原纤维-多磺酸粘多糖在运动恢复过程中进行测量，预先准备，不断输注L-[环13 C6]苯丙氨酸，并收集肌肉活检前和4小时后饮料摄入。在摄入饮料之前和之后的时间点收集血液样品。蛋白质印迹法被用来测量mTORC 1信号蛋白的磷酸化状态在活检收集前，1-，和4小时后喝。BCAA中血浆亮氨酸（300 ± 96%）、异亮氨酸（300 ± 88%）和缬氨酸（144 ± 59%）浓度较基线增加的百分比在饮酒后0.5 h达到峰值。BCAA中S6 K1 Thr 389（P = 0.017）和PRAS 40（P = 0.037）的磷酸化水平高于PLA。BCAA组的肌原纤维-MPS（0.110 ± 0.009%/h）比PLA组（0.090 ± 0.006%/h）高22%（P = 0.012）。饮用后，BCAA组苯丙氨酸Ra（18.00 ± 4.31 μmol·kgBM−1）比PLA组（21.75 ± 4.89 μmol·kgBM−1; P = 0.028）低约6%。我们的结论是，单独服用维生素BCAA增加了运动后肌原纤维-MPS和磷酸化状态mTORC 1信号的刺激。
The ingestion of intact protein or essential amino acids (EAA) stimulates mechanistic target of rapamycin complex-1 (mTORC1) signaling and muscle protein synthesis (MPS) following resistance exercise. The purpose of this study was to investigate the response of myofibrillar-MPS to ingestion of branched-chain amino acids (BCAAs) only (i.e., without concurrent ingestion of other EAA, intact protein, or other macronutrients) following resistance exercise in humans. Ten young (20.1 ± 1.3 years), resistance-trained men completed two trials, ingesting either 5.6 g BCAA or a placebo (PLA) drink immediately after resistance exercise. Myofibrillar-MPS was measured during exercise recovery with a primed, constant infusion of L-[ring13C6] phenylalanine and collection of muscle biopsies pre and 4 h-post drink ingestion. Blood samples were collected at time-points before and after drink ingestion. Western blotting was used to measure the phosphorylation status of mTORC1 signaling proteins in biopsies collected pre, 1-, and 4 h-post drink. The percentage increase from baseline in plasma leucine (300 ± 96%), isoleucine (300 ± 88%), and valine (144 ± 59%) concentrations peaked 0.5 h-post drink in BCAA. A greater phosphorylation status of S6K1Thr389 (P = 0.017) and PRAS40 (P = 0.037) was observed in BCAA than PLA at 1 h-post drink ingestion. Myofibrillar-MPS was 22% higher (P = 0.012) in BCAA (0.110 ± 0.009%/h) than PLA (0.090 ± 0.006%/h). Phenylalanine Ra was ~6% lower in BCAA (18.00 ± 4.31 μmol·kgBM−1) than PLA (21.75 ± 4.89 μmol·kgBM−1; P = 0.028) after drink ingestion. We conclude that ingesting BCAAs alone increases the post-exercise stimulation of myofibrillar-MPS and phosphorylation status mTORC1 signaling.