Hamilton Marc T, Hamilton Deborah G, Zderic Theodore W
Department Health and Human Performance, University of Houston, Houston, TX 77204, USA.
Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA.
iScience. 2022 Aug 5;25(9):104869. doi: 10.1016/j.isci.2022.104869. eCollection 2022 Sep 16.
Slow oxidative muscle, most notably the soleus, is inherently well equipped with the molecular machinery for regulating blood-borne substrates. However, the entire human musculature accounts for only ∼15% of the body's oxidative metabolism of glucose at the resting energy expenditure, despite being the body's largest lean tissue mass. We found the human soleus muscle could raise local oxidative metabolism to high levels for hours without fatigue, during a type of soleus-dominant activity while sitting, even in unfit volunteers. Muscle biopsies revealed there was minimal glycogen use. Magnifying the otherwise negligible local energy expenditure with isolated contractions improved systemic VLDL-triglyceride and glucose homeostasis by a large magnitude, e.g., 52% less postprandial glucose excursion (∼50 mg/dL less between ∼1 and 2 h) with 60% less hyperinsulinemia. Targeting a small oxidative muscle mass (∼1% body mass) with local contractile activity is a potent method for improving systemic metabolic regulation while prolonging the benefits of oxidative metabolism.
慢氧化型肌肉，尤其是比目鱼肌，天生就具备完善的分子机制来调节血液中的底物。然而，尽管肌肉是人体最大的瘦组织群，但在静息能量消耗时，整个人体肌肉组织仅占身体葡萄糖氧化代谢的约15%。我们发现，在一种以比目鱼肌为主导的坐姿活动中，即使是身体状况不佳的志愿者，人类比目鱼肌也能将局部氧化代谢提高到高水平且数小时不疲劳。肌肉活检显示糖原消耗极少。通过孤立收缩放大原本可忽略不计的局部能量消耗，可大幅改善全身极低密度脂蛋白甘油三酯和葡萄糖稳态，例如，餐后血糖波动减少52%（约1至2小时之间减少约50mg/dL），高胰岛素血症减少60%。通过局部收缩活动针对小部分氧化肌肉群（约占体重的1%）是一种有效方法，可改善全身代谢调节，同时延长氧化代谢的益处。
