School of Human Movement Studies, Charles Sturt University, Bathurst, New South Wales, Australia.
J Appl Physiol (1985). 2012 Jun;112(12):1992-2001. doi: 10.1152/japplphysiol.00166.2012. Epub 2012 Apr 5.
We determined myofibrillar and mitochondrial protein fractional synthesis rates (FSR), intramuscular signaling protein phosphorylation, and mRNA expression responses after isolated bouts of resistance exercise (RE), aerobic exercise (AE), or in combination [termed concurrent exercise (CE)] in sedentary middle-aged men. Eight subjects (age = 53.3 ± 1.8 yr; body mass index = 29.4 ± 1.4 kg·m(2)) randomly completed 8 × 8 leg extension repetitions at 70% of one repetition-maximum, 40 min of cycling at 55% peak aerobic power output (AE), or (consecutively) 50% of the RE and AE trials (CE). Biopsies were obtained (during a primed, constant infusion of l-[ring-(13)C(6)]phenylalanine) while fasted, and at 1 and 4 h following postexercise ingestion of 20 g of protein. All trials increased mitochondrial FSR above fasted rates (RE = 1.3-fold; AE = 1.5; CE = 1.4; P < 0.05), although only CE (2.2) and RE (1.8) increased myofibrillar FSR (P < 0.05). At 1 h postexercise, phosphorylation of Akt on Ser(473) (CE = 7.7; RE = 4.6) and Thr(308) (CE = 4.4; RE = 2.9), and PRAS40 on Thr(246) (CE = 3.8; AE = 2.5) increased (P < 0.05), with CE greater than AE for Akt Ser(473)-Thr(308) and greater than RE for PRAS40 (P < 0.05). Despite increased phosphorylation of Akt-PRAS40, phosphorylation of mammalian target of rapamycin (Ser(2448)) remained unchanged (P > 0.05), while rpS6 (Ser(235/236)) increased only in RE (10.4) (P < 0.05). CE and AE both resulted in increased peroxisome proliferator receptor-γ coactivator 1-α (PGC1α) expression at 1 h (CE = 2.9; AE = 2.8; P < 0.05) and 4 h (CE = 2.6; AE = 2.4) and PGC1β expression at 4 h (CE = 2.1; AE = 2.6; P < 0.05). These data suggest that CE-induced acute stimulation of myofibrillar and mitochondrial FSR, protein signaling, and mRNA expression are equivalent to either isolate mode (RE or AE). These results occurred without an interference effect on muscle protein subfractional synthesis rates, protein signaling, or mRNA expression.
我们在久坐的中年男性中分别测定了抗阻运动（RE）、有氧运动（AE）或联合运动（CE）后肌纤维和线粒体蛋白的合成率（FSR）、肌肉内信号蛋白磷酸化和 mRNA 表达的反应。8 名受试者（年龄=53.3±1.8 岁；体重指数=29.4±1.4kg·m(2)）随机完成了 8×8 次腿部伸展重复，强度为 70%的一次重复最大力量，40min 的 55%峰值有氧功率输出（AE），或（连续）50%的 RE 和 AE 试验（CE）。在禁食时以及运动后摄入 20g 蛋白质后的 1 和 4 小时，获得（在 [ring-(13)C(6)]phenylalanine 的预注恒定输注期间）活检。所有试验均使线粒体 FSR 高于空腹水平（RE=1.3 倍；AE=1.5 倍；CE=1.4 倍；P<0.05），尽管只有 CE（2.2）和 RE（1.8）增加了肌纤维 FSR（P<0.05）。在运动后 1 小时，Akt 的 Ser(473)（CE=7.7；RE=4.6）和 Thr(308)（CE=4.4；RE=2.9）以及 PRAS40 的 Thr(246)（CE=3.8；AE=2.5）磷酸化增加（P<0.05），CE 大于 AE 对于 Akt Ser(473)-Thr(308)，CE 大于 RE 对于 PRAS40（P<0.05）。尽管 Akt-PRAS40 的磷酸化增加，但哺乳动物雷帕霉素靶蛋白（Ser(2448)）的磷酸化保持不变（P>0.05），而 rpS6（Ser(235/236)）仅在 RE 中增加（10.4）（P<0.05）。CE 和 AE 在 1 小时（CE=2.9；AE=2.8；P<0.05）和 4 小时（CE=2.6；AE=2.4）时均导致过氧化物酶体增殖物激活受体-γ 共激活因子 1-α（PGC1α）表达增加，以及 4 小时时 PGC1β 表达增加（CE=2.1；AE=2.6；P<0.05）。这些数据表明，CE 诱导的肌纤维和线粒体 FSR、蛋白质信号和 mRNA 表达的急性刺激与任何一种隔离模式（RE 或 AE）相当。这些结果发生在不干扰肌肉蛋白亚组分合成率、蛋白质信号或 mRNA 表达的情况下。
