title: The effect of interleukin-6 and the interleukin-6 receptor on glucose transport in mouse skeletal muscle.
abstract: Exercise results in an increase in interleukin-6 (IL-6), its receptor (IL-6R) and skeletal muscle glucose transport. Interleukin-6 has been found to have equivocal effects on glucose transport, with no studies, to our knowledge, investigating any potential role of IL-6R. In the present study, we hypothesized that a combined preparation of IL-6 and soluble IL-6R (sIL-6R) would stimulate glucose transport. Mouse soleus muscles were incubated with physiological and supraphysiological concentrations of IL-6 and a combination of IL-6 and sIL-6R. Total and phosphorylated AMP-activated protein kinase (AMPK) and Protein Kinase B (PKB/Akt) were also measured by Western blotting. Exposure to both physiological (80 pg ml(-1)) and supraphysiological IL-6 (120 ng ml(-1)) had no effect on glucose transport. At physiological levels, exposure to a combination of IL-6 and sIL-6R (32 ng ml(-1)) resulted in a 1.4-fold increase (P < 0.05) in basal glucose transport with no change to the phosphorylation of AMPK. Exposure to supraphysiological levels of IL-6 and sIL-6R (120 ng ml(-1)) resulted in an approximately twofold increase (P < 0.05) in basal glucose transport and an increase (P < 0.05) in AMPK phosphorylation. No effect of IL-6 or sIL-6R was observed on insulin-stimulated glucose transport. These findings demonstrate that, while IL-6 alone does not stimulate glucose transport in mouse soleus muscle, when sIL-6R is introduced glucose transport is directly stimulated, partly through AMPK-dependent signalling.
authors.affiliation: Department of Sport & Exercise Sciences, Loughborough University, Ashby Road, Loughborough, Leicestershire LE113TU, UK.
authors.forename: Stuart R
authors.initials: SR
authors.lastname: Gray
authors.forename: Aivaras
authors.initials: A
authors.lastname: Ratkevicius
authors.forename: Henning
authors.initials: H
authors.lastname: Wackerhage
authors.forename: Paul
authors.initials: P
authors.lastname: Coats
authors.forename: Myra A
authors.initials: MA
authors.lastname: Nimmo
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology; D015850:Interleukin-6 / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D019947:Receptors, Interleukin-6 / Q000378:metabolism*
chemical_list: D007328:Insulin; D015850:Interleukin-6; D019947:Receptors, Interleukin-6; D051057:Proto-Oncogene Proteins c-akt; D055372:AMP-Activated Protein Kinases; D005947:Glucose