The Centre of Inflammation and Metabolism, Department of Infectious Diseases and CMRC, Rigshospitalet, Section 7641, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 9, DK-2100, Copenhagen, Denmark.
Nat Rev Endocrinol. 2012 Apr 3;8(8):457-65. doi: 10.1038/nrendo.2012.49.
During the past decade, skeletal muscle has been identified as a secretory organ. Accordingly, we have suggested that cytokines and other peptides that are produced, expressed and released by muscle fibres and exert either autocrine, paracrine or endocrine effects should be classified as myokines. The finding that the muscle secretome consists of several hundred secreted peptides provides a conceptual basis and a whole new paradigm for understanding how muscles communicate with other organs, such as adipose tissue, liver, pancreas, bones and brain. However, some myokines exert their effects within the muscle itself. Thus, myostatin, LIF, IL-6 and IL-7 are involved in muscle hypertrophy and myogenesis, whereas BDNF and IL-6 are involved in AMPK-mediated fat oxidation. IL-6 also appears to have systemic effects on the liver, adipose tissue and the immune system, and mediates crosstalk between intestinal L cells and pancreatic islets. Other myokines include the osteogenic factors IGF-1 and FGF-2; FSTL-1, which improves the endothelial function of the vascular system; and the PGC-1α-dependent myokine irisin, which drives brown-fat-like development. Studies in the past few years suggest the existence of yet unidentified factors, secreted from muscle cells, which may influence cancer cell growth and pancreas function. Many proteins produced by skeletal muscle are dependent upon contraction; therefore, physical inactivity probably leads to an altered myokine response, which could provide a potential mechanism for the association between sedentary behaviour and many chronic diseases.
在过去的十年中，骨骼肌已被确定为一种分泌器官。因此，我们建议，由肌肉纤维产生、表达和释放的细胞因子和其他肽，发挥自分泌、旁分泌或内分泌作用，应归类为肌肉因子。发现肌肉分泌组由几百种分泌肽组成，为理解肌肉如何与其他器官（如脂肪组织、肝脏、胰腺、骨骼和大脑）进行通讯提供了概念基础和全新的范例。然而，一些肌肉因子在肌肉本身发挥作用。因此，肌肉生长抑制素、LIF、IL-6 和 IL-7 参与肌肉肥大和肌发生，而 BDNF 和 IL-6 参与 AMPK 介导的脂肪氧化。IL-6 似乎对肝脏、脂肪组织和免疫系统也有全身作用，并介导肠 L 细胞和胰岛之间的串扰。其他肌肉因子包括成骨因子 IGF-1 和 FGF-2；FSTL-1 可改善血管系统的内皮功能；以及 PGC-1α 依赖性肌肉因子鸢尾素，可促进棕色脂肪样发育。过去几年的研究表明，存在尚未被识别的因子，由肌肉细胞分泌，可能影响癌细胞生长和胰腺功能。骨骼肌产生的许多蛋白质都依赖于收缩；因此，缺乏体力活动可能导致肌肉因子反应改变，这可能为久坐行为与许多慢性疾病之间的关联提供了一个潜在的机制。
