title: Skeletal muscle interleukin-6 regulates metabolic factors in iWAT during HFD and exercise training.
abstract: OBJECTIVE
  To investigate the role of skeletal muscle (SkM) interleukin (IL)-6 in the regulation of adipose tissue metabolism.
  
  
  METHODS
  Muscle-specific IL-6 knockout (IL-6 MKO) and IL-6(loxP/loxP) (Floxed) mice were subjected to standard rodent diet (Chow), high-fat diet (HFD), or HFD in combination with exercise training (HFD ExTr) for 16 weeks.
  
  
  RESULTS
  Total fat mass increased (P < 0.05) in both genotypes with HFD. However, HFD IL-6 MKO mice had lower (P < 0.05) inguinal adipose tissue (iWAT) mass than HFD Floxed mice. Accordingly, iWAT glucose transporter 4 (GLUT4) protein content, 5'AMP activated protein kinase (AMPK)(Thr172) phosphorylation, and fatty acid synthase (FAS) mRNA content were lower (P < 0.05) in IL-6 MKO than Floxed mice on Chow. In addition, iWAT AMPK(Thr172) and hormone-sensitive lipase (HSL)(Ser565) phosphorylation as well as perilipin protein content was higher (P < 0.05) in HFD IL-6 MKO than HFD Floxed mice, and pyruvate dehydrogenase E1α (PDH-E1α) protein content was higher (P < 0.05) in HFD ExTr IL-6 MKO than HFD ExTr Floxed mice.
  
  
  CONCLUSIONS
  These findings indicate that SkM IL-6 affects iWAT mass through regulation of glucose uptake capacity as well as lipogenic and lipolytic factors.
authors.affiliation: Department of Biology, Centre for Inflammation and Metabolism, The August Krogh Centre, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Jakob G
authors.initials: JG
authors.lastname: Knudsen
authors.affiliation: Department of Biology, Centre for Inflammation and Metabolism, The August Krogh Centre, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Laerke
authors.initials: L
authors.lastname: Bertholdt
authors.affiliation: Department of Biology, Centre for Inflammation and Metabolism, The August Krogh Centre, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Ella
authors.initials: E
authors.lastname: Joensen
authors.affiliation: Department of Biology, Centre for Inflammation and Metabolism, The August Krogh Centre, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Signe B
authors.initials: SB
authors.lastname: Lassen
authors.affiliation: Departamento die Biología Celular y Fisiología, Universidad De Autonoma De Barcelona, Barcelona, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Hidalgo
authors.affiliation: Department of Biology, Centre for Inflammation and Metabolism, The August Krogh Centre, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Henriette
authors.initials: H
authors.lastname: Pilegaard
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D059305:Diet, High-Fat; D015850:Interleukin-6 / Q000737:chemistry* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000737:chemistry*; D010805:Physical Conditioning, Animal / Q000502:physiology
chemical_list: D015850:Interleukin-6; C577686:interleukin-6, mouse