Contraction-Induced Myokine Production and Release: Is Skeletal Muscle an Endocrine Organ?

@article{Febbraio2005ContractionInducedMP,
  title={Contraction-Induced Myokine Production and Release: Is Skeletal Muscle an Endocrine Organ?},
  author={Mark A. Febbraio and Bente Klarlund Pedersen},
  journal={Exercise and Sport Sciences Reviews},
  year={2005},
  volume={33},
  pages={114-119}
}
The concentration of plasma interleukin-6 (IL-6) increases during physical exercise, but until recently the cellular origin of this increase has been unknown. Recent work has identified that skeletal muscle is a major source of this increase and the release of IL-6 from muscle can mediate metabolic processes. IL-6 is, therefore, the first identified “myokine” released from muscle that can now be termed an endocrine organ. 
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The discovery that contracting skeletal muscle secretes proteins sets a novel paradigm: skeletal muscle is an endocrine organ producing and releasing myokines, which work in a hormone-like fashion, exerting specific endocrine effects on other organs.
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