title: Skeletal muscle composition in dietary obesity-susceptible and dietary obesity-resistant rats.
abstract: The intent of this study was to determine whether a relationship exists between susceptibility to high-fat diet (HFD)-induced obesity and skeletal muscle fiber type. Forty-four adult male Wistar rats were given ad libitum access to a HFD (60% of calories from fat) for 4 wk. Rats were then grouped into quartiles for total weight gain, and the top-quartile [obesity prone (OP)] rats were compared with the bottom-quartile [obesity resistant (OR)] rats. OP rats gained 1.5 times as much weight as OR rats. OR rats had a significantly higher proportion of type I muscle fibers in the medial head of the gastrocnemius muscle than OP rats both before (determined from a muscle biopsy) and after the HFD feeding period. A greater proportion of type I fibers may be associated with a greater capacity for fat oxidation, which would favor resistance to body fat accumulation. Preexisting differences in muscle fiber composition may play a role in determining susceptibility to dietary obesity.
authors.affiliation: Department of Pediatrics, Vanderbilt University, Nashville, Tennessee 37232.
authors.forename: J
authors.initials: J
authors.lastname: Abou Mrad
authors.forename: F
authors.initials: F
authors.lastname: Yakubu
authors.forename: D
authors.initials: D
authors.lastname: Lin
authors.forename: J C
authors.initials: JC
authors.lastname: Peters
authors.forename: J B
authors.initials: JB
authors.lastname: Atkinson
authors.forename: J O
authors.initials: JO
authors.lastname: Hill
mesh_terms: D000818:Animals; D001823:Body Composition; D001835:Body Weight; D004032:Diet; D004198:Disease Susceptibility; D008297:Male; D009132:Muscles / Q000473:pathology*; D009765:Obesity / Q000209:etiology* / Q000473:pathology; D051381:Rats; D011919:Rats, Inbred Strains