title: Effect of exercise, training, and glycogen availability on IL-6 receptor expression in human skeletal muscle.
abstract: The cytokine interleukin-6 (IL-6) exerts it actions via the IL-6 receptor (IL-6R) in conjunction with the ubiquitously expressed gp130 receptor. IL-6 is tightly regulated in response to exercise, being affected by factors such as exercise intensity and duration, as well as energy availability. Although the IL-6 response to exercise has been extensively studied, little is known about the regulation of the IL-6R response. In the present study, we aimed to investigate the effect of exercise, training, and glycogen availability, factors known to affect IL-6, on the regulation of gene expression of the IL-6R in human skeletal muscle. Human subjects performed either 10 wk of training with an acute exercise bout before and after the training period, or a low-glycogen vs. normal-glycogen acute exercise trial. The IL-6R mRNA response was evaluated in both trials. In response to acute exercise, an increase in IL-6R mRNA levels was observed. Neither training nor intramuscular glycogen levels had an effect on the IL-6R mRNA response to exercise. However, after 10 wk of training, the skeletal muscle expressed a higher mRNA level of IL-6R compared with before training. The present study demonstrated that the IL-6R gene expression levels in skeletal muscle are increased in response to acute exercise, a response that is very well conserved, being affected by neither training status nor intramuscular glycogen levels, as opposed to IL-6. However, after the training period, IL-6R mRNA production was increased in skeletal muscle, suggesting a sensitization of skeletal muscle to IL-6 at rest.
authors.affiliation: Department of Infectious Disease, Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Denmark. ckeller@inflammation-metabolism.dk
authors.forename: Charlotte
authors.initials: C
authors.lastname: Keller
authors.forename: Adam
authors.initials: A
authors.lastname: Steensberg
authors.forename: Anne K
authors.initials: AK
authors.lastname: Hansen
authors.forename: Christian P
authors.initials: CP
authors.lastname: Fischer
authors.forename: Peter
authors.initials: P
authors.lastname: Plomgaard
authors.forename: Bente Klarlund
authors.initials: BK
authors.lastname: Pedersen
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D015444:Exercise / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology; D006003:Glycogen / Q000378:metabolism*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D019947:Receptors, Interleukin-6 / Q000378:metabolism*
chemical_list: D019947:Receptors, Interleukin-6; D006003:Glycogen