Center for Metabolic and Vascular Biology, Arizona State University, Tempe, Arizona, USA.
School of Nutrition and Health Promotion, Arizona State University, Phoenix, Arizona, USA.
Obesity (Silver Spring). 2018 Jul;26(7):1179-1187. doi: 10.1002/oby.22213. Epub 2018 Jun 12.
Obesity alters protein metabolism in skeletal muscle, but consistent evidence is lacking. This study compared muscle protein synthesis in adults with obesity and in lean controls in the fasted state and during an amino acid infusion.
Ten subjects with obesity (age: 36 ± 3 years; BMI: 34 ± 1 kg/m ) and ten controls (age: 35 ± 3 years; BMI: 23 ± 1 kg/m ) received an infusion of L-[2,3,3,4,5,5,5,6,6,6- H ]leucine (0.15 μmol/kg fat-free mass/min) to measure muscle protein synthesis after an overnight fast and during amino acid infusion.
Despite greater muscle mammalian target of rapamycin phosphorylation (P ≤ 0.05), fasted-state mixed-muscle and mitochondrial protein synthesis were lower in subjects with obesity (P ≤ 0.05). However, the change in mixed-muscle protein synthesis during the amino acid infusion was 2.7-fold greater in subjects with obesity (P ≤ 0.05), accompanied by a greater change in S6 kinase-1 phosphorylation (P ≤ 0.05). The change in mitochondrial protein synthesis did not differ between groups (P > 0.05).
Adults with obesity have reduced muscle protein synthesis in the fasted state, but this response is compensated for by a greater change in overall muscle protein synthesis during amino acid infusion.
肥胖会改变骨骼肌的蛋白质代谢，但目前仍缺乏一致性证据。本研究比较了肥胖成年人和瘦对照者在空腹和氨基酸输注期间的肌肉蛋白质合成。
10 名肥胖受试者（年龄：36±3 岁；BMI：34±1 kg/m ）和 10 名对照者（年龄：35±3 岁；BMI：23±1 kg/m ）接受 L-[2,3,3,4,5,5,5,6,6,6- H ]亮氨酸输注（0.15 μmol/kg 去脂体重/min），以测量空腹和氨基酸输注期间的肌肉蛋白质合成。
尽管肥胖者的肌肉哺乳动物雷帕霉素靶蛋白磷酸化更高（P≤0.05），但空腹状态下的混合肌肉和线粒体蛋白质合成较低（P≤0.05）。然而，肥胖者在氨基酸输注期间混合肌肉蛋白质合成的变化增加了 2.7 倍（P≤0.05），同时 S6 激酶-1 磷酸化的变化也更大（P≤0.05）。线粒体蛋白质合成的变化在两组之间没有差异（P>0.05）。
肥胖成年人在空腹状态下的肌肉蛋白质合成减少，但在氨基酸输注期间，整体肌肉蛋白质合成的变化得到了补偿。
