title: Interleukin-6 stimulates lipolysis and fat oxidation in humans.
abstract: Although IL-6 is a key modulator of immune function, it also plays a role in regulating substrate metabolism. To determine whether IL-6 affects lipid metabolism, 18 healthy men were infused for 3 h with saline (Con; n = 6) or a high dose (High-rhIL6; n = 6) or a low dose (Low-rhIL6; n = 6) of recombinant human IL-6 (rhIL-6). The IL-6 concentration during Con, Low-rhIL6, and High-rhIL6 was at a steady state after 30 min of infusion at approximately 4, 140, and 320 pg/ml, respectively. Either dose of rhIL-6 was associated with a similar increase in fatty acid (FA) concentration and endogenous FA rate of appearance (R(a)) from 90 min after the start of the infusion. The FA concentration and FA R(a) continued to increase until the cessation of rhIL-6 infusion, reaching levels approximately 50% greater than Con values. The elevated levels reached at the end of rhIL-6 infusion persisted at least 3 h postinfusion. Triacylglycerol concentrations were unchanged during rhIL-6 infusion, whereas whole body fat oxidation increased after the second hour of rhIL-6 infusion. Of note, during Low-rhIL6, the induced elevation in FA concentration and FA R(a) occurred in the absence of any change in adrenaline, insulin, or glucagon, and no adverse side effects were observed. In conclusion, the data identify IL-6 as a potent modulator of fat metabolism in humans, increasing fat oxidation and FA reesterification without causing hypertriacylglyceridemia.
authors.affiliation: Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, DK-2100 Copenhagen, Denmark. gvhall@cmrc.dk
authors.forename: Gerrit
authors.initials: G
authors.lastname: van Hall
authors.forename: Adam
authors.initials: A
authors.lastname: Steensberg
authors.forename: Massimo
authors.initials: M
authors.lastname: Sacchetti
authors.forename: Christian
authors.initials: C
authors.lastname: Fischer
authors.forename: Charlotte
authors.initials: C
authors.lastname: Keller
authors.forename: Peter
authors.initials: P
authors.lastname: Schjerling
authors.forename: Natalie
authors.initials: N
authors.lastname: Hiscock
authors.forename: Kirsten
authors.initials: K
authors.lastname: Møller
authors.forename: Bengt
authors.initials: B
authors.lastname: Saltin
authors.forename: Mark A
authors.initials: MA
authors.lastname: Febbraio
authors.forename: Bente K
authors.initials: BK
authors.lastname: Pedersen
mesh_terms: D000328:Adult; D004734:Energy Metabolism / Q000187:drug effects* / Q000276:immunology; D004837:Epinephrine / Q000097:blood; D005227:Fatty Acids / Q000378:metabolism*; D005934:Glucagon / Q000097:blood; D005990:Glycerol / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D015850:Interleukin-6 / Q000008:administration & dosage* / Q000378:metabolism; D008066:Lipolysis / Q000187:drug effects* / Q000276:immunology; D008297:Male; D009638:Norepinephrine / Q000097:blood; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000187:drug effects / Q000276:immunology; D011994:Recombinant Proteins / Q000008:administration & dosage; D014280:Triglycerides / Q000378:metabolism
chemical_list: D005227:Fatty Acids; D007328:Insulin; D015850:Interleukin-6; D011994:Recombinant Proteins; D014280:Triglycerides; D005934:Glucagon; D005990:Glycerol; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine