Feeding meals containing soy or whey protein after exercise stimulates protein synthesis and translation initiation in the skeletal muscle of male rats
Feeding meals containing soy or whey protein after exercise stimulates protein synthesis and translation initiation in the skeletal muscle of male rats
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DOI：
10.1093/jn/137.2.357
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发表时间：
2007-02-01
影响因子：
4.2
通讯作者：
McNurlan, Margaret A.
中科院分区：
文献类型：
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作者：
Anthony, Tracy G.;McDaniel, Brent J.;McNurlan, Margaret A.
本研究的目的是比较骨骼肌蛋白质合成和翻译启动的早期反应后，摄入不同的蛋白质来源的耐力运动。跑步机驯化大鼠被指定为非运动对照组（NEX）或跑步机行使2小时，在26米/分钟（类似于75%VO2max），然后喂碳水化合物（EC），碳水化合物加大豆蛋白（ES），或碳水化合物加乳清蛋白（EW）。运动后1h，EC、ES、EW组血清胰岛素浓度均高于NEX组（P < 0.05），EW组高于EC组，ES组居中。血清支链氨基酸含量ES组和EW组均高于EC组，但血清亮氨酸和异亮氨酸含量EW组高于ES组（P < 0.05）。然而，ES和EW促进骨骼肌蛋白质合成的分数率显着高于EC。同样，与EC相比，ES和EW均增加mRNA帽结合复合物eIF 4F的形成，并刺激翻译阻遏物4 E-BP 1、70 kD核糖体蛋白S6激酶（S6 K1）和哺乳动物雷帕霉素靶蛋白（mTOR）激酶在丝氨酸2448处的磷酸化。另一方面，EW组S6 K1和mTOR的磷酸化水平高于ES组（P < 0.05）。总之，大豆蛋白和乳清蛋白可促进运动大鼠骨骼肌的蛋白质合成和mRNA帽结合步骤。此外，数据表明骨骼肌中的mTOR信号传导对饮食氨基酸的生理变化有强烈反应。
The purpose of this investigation was to compare the early response of skeletal muscle protein synthesis and translation initiation following the ingestion of different protein sources after endurance exercise. Treadmill-acclimated rats were designated as either nonexercised controls (NEX) or treadmill exercised for 2 h at 26 m/min (similar to 75% VO2max) and then fed either carbohydrate only (EC), carbohydrate plus soy protein (ES), or carbohydrate plus whey protein (EW). One hour after exercise, serum insulin concentrations in EC, ES, and EW were greater than in NEX (P < 0.05), the concentration in EW was greater than in EC, with that in ES intermediate. Serum concentrations of branched-chain amino acids in ES and EW were higher than in EC, but serum leucine and isoleucine in EW were higher than in ES (P < 0.05). Nevertheless, both ES and EW promoted the fractional rate of skeletal muscle protein synthesis significantly more than EC. Likewise, compared with EC, both ES and EW increased formation of the mRNA cap binding complex elF4F and stimulated phosphorylation of the translational repressor, 4E-BP1, the 70kD rilbosomal protein S6 kinase (S6K1), and the mammalian target of rapamycin (mTOR) kinase at serine 2448. On the other hand, phosphorylation of S6K1 and mTOR was greater in EW than in ES (P < 0.05). In conclusion, general protein synthesis and the mRNA cap binding step are promoted comparably by soy protein and whey protein in the skeletal muscle of exercised rats. Furthermore, the data suggest that mTOR signaling in skeletal muscle is acutely responsive to physiological variations in dietary amino acids.