Centre of Healthy Ageing, Department of Biomedical Sciences, University of Copenhagen, Denmark.
Exp Physiol. 2011 Jun;96(6):590-8. doi: 10.1113/expphysiol.2010.056424. Epub 2011 Mar 18.
Exercising muscle releases interleukin-6 (IL-6), but the mechanisms controlling this process are poorly understood. This study was performed to test the hypothesis that the IL-6 release differs in arm and leg muscle during whole-body exercise, owing to differences in muscle metabolism. Sixteen subjects (10 men and six women, with body mass index 24 ± 1 kg m(-2) and peak oxygen uptake 3.4 ± 0.6 l min(-1)) performed a 90 min combined arm and leg cycle exercise at 60% of maximal oxygen uptake. The subjects arrived at the laboratory having fasted overnight, and catheters were placed in the femoral artery and vein and in the subclavian vein. During exercise, arterial and venous limb blood was sampled and arm and leg blood flow were measured by thermodilution. Lean limb mass was measured by dual-energy X-ray absorbtiometry scanning. Before and after exercise, biopsies were obtained from vastus lateralis and deltoideus. During exercise, IL-6 release was similar between men and women and higher (P < 0.05) from arms than legs (1.01 ± 0.42 and 0.33 ± 0.12 ng min(-1) (kg lean limb mass)(-1), respectively). Blood flow (425 ± 36 and 554 ± 35 ml min(-1) (kg lean limb mass)(-1)) and fatty acid uptake (26 ± 7 and 47 ± 7 μmol min(-1) (kg lean limb mass)(-1)) were lower, glucose uptake similar (51 ± 12 and 41 ± 8 mmol min(-1) (kg lean limb mass)(-1)) and lactate release higher (82 ± 32 and -2 ± 12 μmol min(-1) (kg lean limb mass)(-1)) in arms than legs, respectively, during exercise (P < 0.05). No correlations were present between IL-6 release and exogenous substrate uptakes. Muscle glycogen was similar in arms and legs before exercise (388 ± 22 and 428 ± 25 mmol (kg dry weight)(-1)), but after exercise it was only significantly lower in the leg (219 ± 29 mmol (kg dry weight)(-1)). The novel finding of a markedly higher IL-6 release from the exercising arm compared with the leg during whole-body exercise was not directly correlated to release or uptake of exogenous substrate, nor to muscle glycogen utilization.
运动肌肉会释放白细胞介素-6（IL-6），但控制这一过程的机制尚不清楚。本研究旨在验证以下假设：由于肌肉代谢的差异，全身运动时手臂和腿部肌肉的 IL-6 释放情况不同。16 名受试者（10 名男性和 6 名女性，体重指数 24 ± 1kg/m2，峰值摄氧量 3.4 ± 0.6l/min）以最大摄氧量的 60%进行了 90 分钟的上肢和下肢联合自行车运动。受试者空腹过夜到达实验室，股动脉和静脉以及锁骨下静脉放置导管。运动期间，通过热稀释法采样动脉和静脉肢体血液，并测量手臂和腿部血流。使用双能 X 射线吸收仪扫描测量瘦肢体质量。运动前后，从股外侧肌和三角肌获取活检。运动期间，男女之间的 IL-6 释放相似，手臂的释放高于腿部（分别为 1.01 ± 0.42 和 0.33 ± 0.12ng min-1（kg 瘦肢体质量）-1）（P <0.05）。血流（425 ± 36 和 554 ± 35ml min-1（kg 瘦肢体质量）-1）和脂肪酸摄取（26 ± 7 和 47 ± 7μmol min-1（kg 瘦肢体质量）-1）分别较低，葡萄糖摄取相似（51 ± 12 和 41 ± 8mmol min-1（kg 瘦肢体质量）-1），运动时手臂的乳酸释放高于腿部（分别为 82 ± 32 和-2 ± 12μmol min-1（kg 瘦肢体质量）-1）（P <0.05）。IL-6 释放与外源性底物摄取之间无相关性。运动前手臂和腿部的肌肉糖原相似（388 ± 22 和 428 ± 25mmol（kg 干重）-1），但运动后腿部仅显著降低（219 ± 29mmol（kg 干重）-1）。全身运动时，与腿部相比，手臂的 IL-6 释放明显更高，这一新发现与外源性底物的释放或摄取或肌肉糖原利用无关。
