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Cellular and Biochemical Features of Skeletal Muscle in Obese Yucatan Minipigs
Author(s) -
GuillermRegost Christelle,
Louveau Isabelle,
Sébert Sylvain P.,
Damon Marie,
Champ Martine M.,
Gondret Florence
Publication year - 2006
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1038/oby.2006.195
Subject(s) - endocrinology , medicine , skeletal muscle , intramuscular fat , carnitine , citrate synthase , lipogenesis , lipolysis , biology , lipid metabolism , glut4 , adipose tissue , insulin , glucose uptake , biochemistry , enzyme
Objective: To examine cellular and biochemical features of skeletal muscle in response to dietary‐induced obesity in a novel Yucatan minipig model of childhood obesity. Research Methods and Procedures: From 4 to 16 months of age, minipigs were fed either a recommended human‐type diet (NF; n = 4) or were overfed a western‐type diet with saturated fat and high‐glycemic index carbohydrates (OF, n = 4). Muscle samples (biceps femoris) were histochemically stained for the identification of intramuscular adipocytes, intramyocellular lipid aggregates (oil red O), and myofiber types (myosin ATPase, succinate dehydrogenase). Gene expressions and/or activities of factors involved in lipogenesis, lipolysis, or energetic metabolism were quantified in muscle. Results: Cross‐sectional areas of myofibers paralleled pig body weight ( r = 0.86, p < 0.01). The size of intramuscular adipocytes, the relative proportion of oil red O‐stained fibers, and total muscle lipid content tended ( p ≤ 0.10) to increase in response to OF diet. Hormone‐sensitive lipase, carnitine palmityl transferase‐I , and uncoupling protein 2 mRNA levels were lower ( p < 0.05) in OF pigs than in NF pigs. Activities of β‐hydroxyacyl‐coenzyme A dehydrogenase and citrate synthase assessing post‐carnitine palmityl transferase I events and the proportion of oxidative myofibers were not altered by OF diet. Activity and gene expression of fatty acid synthase were lower ( p < 0.02) in OF pigs than in NF pigs. Discussion: Overfeeding in Yucatan minipigs reduced the expression levels of three catabolic steps in skeletal muscle that are involved also in the etiology of human obesity.