title: Carnitine supplementation to obese Zucker rats prevents obesity-induced type II to type I muscle fiber transition and favors an oxidative phenotype of skeletal muscle.
abstract: In the present study, we tested the hypothesis that carnitine supplementation counteracts obesity-induced muscle fiber transition from type I to type II.
  
  
  
  24 obese Zucker rats were randomly divided into two groups of 12 rats each (obese control, obese carnitine) and 12 lean Zucker rats were selected for lean control group. A control diet was given to both control groups and a carnitine supplemented diet (3 g/kg diet) was given to obese carnitine group for 4 wk. Components of the muscle fiber transformation in skeletal muscle were examined.
  
  
  
  The plasma level of carnitine were lower in the obese control group compared to the lean control group and higher in the obese carnitine group than in the other groups (P < 0.05). Plasma concentrations of triglycerides and non-esterified fatty acids were increased in obese animals compared to lean animals and the obese carnitine group had lower level compared to the obese control group (P < 0.05). The obese carnitine group had an increased number of type I muscle fibers and higher mRNA levels of type I fiber-specific myosin heavy chain, regulators of muscle fiber transition and of genes involved in carnitine uptake, fatty acid transport, β-oxidation, angiogenesis, tricarboxylic acid cycle and thermo genesis in M. rectus femoris compared to the other groups (P < 0.05).
  
  
  
  The results demonstrate that carnitine supplementation to obese Zucker a rat counteracts the obesity-induced muscle fiber transition and restores the muscle oxidative metabolic phenotype. Carnitine supplementation is supposed to be beneficial for the treatment of elevated levels of plasma lipids during obesity or diabetes.
authors.affiliation: Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35390 Giessen, Germany.
authors.forename: Aline
authors.initials: A
authors.lastname: Couturier
authors.affiliation: Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35390 Giessen, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Ringseis
authors.affiliation: Department of Sports Medicine, Justus-Liebig-University Giessen, Kugelberg 62, 35394 Giessen, Germany.
authors.forename: Frank-Christoph
authors.initials: FC
authors.lastname: Mooren
authors.affiliation: Department of Sports Medicine, Justus-Liebig-University Giessen, Kugelberg 62, 35394 Giessen, Germany.
authors.forename: Karsten
authors.initials: K
authors.lastname: Krüger
authors.affiliation: Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35390 Giessen, Germany.
authors.forename: Erika
authors.initials: E
authors.lastname: Most
authors.affiliation: Institute of Animal Nutrition and Nutrition Physiology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, 35390 Giessen, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Eder
keywords: Carnitine; Fatty acid oxidation; Muscle fiber transition; Oxidative capacity; Type I fiber; Zucker rat