Interleukin-6 production in contracting human skeletal muscle is influenced by pre-exercise muscle glycogen content

Authors

  • Adam Steensberg,

    1. The Copenhagen Muscle Research Centre, University of Copenhagen, Denmark
    2. The Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, Denmark
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  • Mark A. Febbraio,

    1. The Copenhagen Muscle Research Centre, University of Copenhagen, Denmark
    2. Exercise Physiology and Metabolism Laboratory, Department of Physiology, The University of Melbourne, Australia
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  • Takuya Osada,

    1. The Copenhagen Muscle Research Centre, University of Copenhagen, Denmark
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  • Peter Schjerling,

    1. The Copenhagen Muscle Research Centre, University of Copenhagen, Denmark
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  • Gerrit van Hall,

    1. The Copenhagen Muscle Research Centre, University of Copenhagen, Denmark
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  • Bengt Saltin,

    1. The Copenhagen Muscle Research Centre, University of Copenhagen, Denmark
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  • Bente Klarlund Pedersen

    Corresponding author
    1. The Copenhagen Muscle Research Centre, University of Copenhagen, Denmark
    2. The Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, Denmark
    • Corresponding author
      B. K. Pedersen: The Department of Infectious Diseases and the Copenhagen Muscle Research Centre, Rigshospitalet 7652, Blegdamsvej 9, DK-2100 Copenhagen N, Denmark., Email: bkp@rh.dk

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Abstract

  • 1Prolonged exercise results in a progressive decline in glycogen content and a concomitant increase in the release of the cytokine interleukin-6 (IL-6) from contracting muscle. This study tests the hypothesis that the exercise-induced IL-6 release from contracting muscle is linked to the intramuscular glycogen availability.
  • 2Seven men performed 5 h of a two-legged knee-extensor exercise, with one leg with normal, and one leg with reduced, muscle glycogen content. Muscle biopsies were obtained before (pre-ex), immediately after (end-ex) and 3 h into recovery (3 h rec) from exercise in both legs. In addition, catheters were placed in one femoral artery and both femoral veins and blood was sampled from these catheters prior to exercise and at 1 h intervals during exercise and into recovery.
  • 3Pre-exercise glycogen content was lower in the glycogen-depleted leg compared with the control leg. Intramuscular IL-6 mRNA levels increased with exercise in both legs, but this increase was augmented in the leg having the lowest glycogen content at end-ex. The arterial plasma concentration of IL-6 increased from 0.6 ± 0.1 ng l−1 pre-ex to 21.7 ± 5.6 ng l−1 end-ex. The depleted leg had already released IL-6 after 1 h (4.38 ± 2.80 ng min−1 (P < 0.05)), whereas no significant release was observed in the control leg (0.36 ± 0.14 ng min−1). A significant net IL-6 release was not observed until 2 h in the control leg.
  • 4This study demonstrates that glycogen availability is associated with alterations in the rate of IL-6 production and release in contracting skeletal muscle.

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