title: Fast/Glycolytic muscle fiber growth reduces fat mass and improves metabolic parameters in obese mice.
abstract: In contrast to the well-established role of oxidative muscle fibers in regulating whole-body metabolism, little is known about the function of fast/glycolytic muscle fibers in these processes. Here, we generated a skeletal muscle-specific, conditional transgenic mouse expressing a constitutively active form of Akt1. Transgene activation led to muscle hypertrophy due to the growth of type IIb muscle fibers, which was accompanied by an increase in strength. Akt1 transgene induction in diet-induced obese mice led to reductions in body weight and fat mass, resolution of hepatic steatosis, and improved metabolic parameters. Akt1-mediated skeletal muscle growth opposed the effects of a high-fat/high-sucrose diet on transcript expression patterns in the liver and increased hepatic fatty acid oxidation and ketone body production. Our findings indicate that an increase in fast/glycolytic muscle mass can result in the regression of obesity and metabolic improvement through its ability to alter fatty acid oxidation in remote tissues.
authors.affiliation: Molecular Cardiology, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118, USA.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Izumiya
authors.forename: Teresa
authors.initials: T
authors.lastname: Hopkins
authors.forename: Carl
authors.initials: C
authors.lastname: Morris
authors.forename: Kaori
authors.initials: K
authors.lastname: Sato
authors.forename: Ling
authors.initials: L
authors.lastname: Zeng
authors.forename: Jason
authors.initials: J
authors.lastname: Viereck
authors.forename: James A
authors.initials: JA
authors.lastname: Hamilton
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Ouchi
authors.forename: Nathan K
authors.initials: NK
authors.lastname: LeBrasseur
authors.forename: Kenneth
authors.initials: K
authors.lastname: Walsh
mesh_terms: D000273:Adipose Tissue; D000818:Animals; D050356:Lipid Metabolism / Q000502:physiology*; D051379:Mice; D008820:Mice, Obese; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D018482:Muscle, Skeletal / Q000254:growth & development*; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology*; D015431:Weight Loss
chemical_list: D051057:Proto-Oncogene Proteins c-akt