Leucine-enriched essential amino acid and carbohydrate ingestion following resistance exercise enhances mTOR signaling and protein synthesis in human muscle
Leucine-enriched essential amino acid and carbohydrate ingestion following resistance exercise enhances mTOR signaling and protein synthesis in human muscle
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DOI：
10.1152/ajpendo.00582.2007
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发表时间：
2008-02-01
影响因子：
5.1
通讯作者：
Rasmussen, Blake B.
中科院分区：
文献类型：
--
作者：
Dreyer, Hans C.;Drummond, Micah J.;Rasmussen, Blake B.
我们最近发现，抗阻运动和摄入必需氨基酸和碳水化合物（EAA + CHO）可以独立地刺激哺乳动物雷帕霉素靶蛋白（mTOR）信号传导和肌肉蛋白合成。运动后提供EAA + CHO溶液可进一步增加肌肉蛋白质合成。因此，我们假设，增强mTOR信号传导可能是负责更大的肌肉蛋白质合成时，富含亮氨酸的EAA + CHO在运动后恢复摄入。将16名男性受试者随机分配至两组之一（对照组或EAA + CHO组）。EAA + CHO组于抗阻运动后1h开始灌胃。通过免疫印迹从重复的肌肉活检样品评估mTOR信号传导。采用稳定性同位素技术测定混合肌合成率（FSR）。运动时肌肉蛋白质合成和4 E-BP 1磷酸化水平显著降低（P < 0.05）。运动后1 h两组FSR均高于基线水平，运动后2 h EAA + CHO组FSR进一步升高（P < 0.05）。FSR的增加与mTOR和S6 K1的磷酸化增强有关（P < 0.05）。对照组Akt磷酸化水平在1h时升高，2 h时恢复至基线水平，而EAA + CHO组Akt磷酸化水平仍保持升高（P < 0.05）。4 E-BP 1磷酸化在对照组恢复期间恢复至基线，但在摄入EAA + CHO时升高（P < 0.05）。运动后1h和2 h，两组大鼠eEF 2磷酸化水平均降低，差异有统计学意义（P < 0.05）。我们的数据表明，增强激活的mTOR信号通路发挥作用，在更大的肌肉蛋白质的合成时，阻力运动后EAA + CHO摄入。
We recently showed that resistance exercise and ingestion of essential amino acids with carbohydrate (EAA + CHO) can independently stimulate mammalian target of rapamycin (mTOR) signaling and muscle protein synthesis in humans. Providing an EAA + CHO solution postexercise can further increase muscle protein synthesis. Therefore, we hypothesized that enhanced mTOR signaling might be responsible for the greater muscle protein synthesis when leucine-enriched EAA + CHOs are ingested during postexercise recovery. Sixteen male subjects were randomized to one of two groups (control or EAA + CHO). The EAA + CHO group ingested the nutrient solution 1 h after resistance exercise. mTOR signaling was assessed by immunoblotting from repeated muscle biopsy samples. Mixed muscle fractional synthetic rate (FSR) was measured using stable isotope techniques. Muscle protein synthesis and 4E-BP1 phosphorylation during exercise were significantly reduced (P < 0.05). Postexercise FSR was elevated above baseline in both groups at 1 h but was even further elevated in the EAA + CHO group at 2 h postexercise (P < 0.05). Increased FSR was associated with enhanced phosphorylation of mTOR and S6K1 (P < 0.05). Akt phosphorylation was elevated at 1 h and returned to baseline by 2 h in the control group, but it remained elevated in the EAA + CHO group (P < 0.05). 4E- BP1 phosphorylation returned to baseline during recovery in control but became elevated when EAA + CHO was ingested (P < 0.05). eEF2 phosphorylation decreased at 1 and 2 h postexercise to a similar extent in both groups (P < 0.05). Our data suggest that enhanced activation of the mTOR signaling pathway is playing a role in the greater synthesis of muscle proteins when resistance exercise is followed by EAA + CHO ingestion.