Abstract
Regional fat distribution is an important determinant of insulin resistance in obesity. In the current study, the relationship between skeletal muscle insulin sensitivity, mid-thigh muscle composition, and the metabolic profile of muscle was investigated. Muscle composition was assessed by computed tomography of the mid-thigh, and by activities of marker enzymes of aerobic-oxidative and glycolytic pathways and muscle fiber typing using biopsies of the vastus lateralis muscle. Muscle with reduced Hounsfield attenuation on computed tomography scans was increased in proportion to obesity, and was strongly related to insulin resistance, reduced muscle oxidative capacity, and increased anaerobic and glycolytic capacities by muscle. These findings suggest that as part of its expression of insulin resistance, skeletal muscle of obese individuals is also poorly equipped for substrate oxidation and manifests increased storage of fat.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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3-Hydroxyacyl CoA Dehydrogenases / metabolism
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Adenosine Triphosphatases / metabolism
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Adipose Tissue / anatomy & histology
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Adult
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Aerobiosis
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Blood Glucose / drug effects
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Blood Glucose / metabolism
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Body Mass Index
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Citrate (si)-Synthase / metabolism
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Creatine Kinase / metabolism
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Electron Transport Complex IV / metabolism
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Female
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Glucose / metabolism
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Glucose Clamp Technique
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Glyceraldehyde-3-Phosphate Dehydrogenases / metabolism
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Glycolysis*
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Hexokinase / metabolism
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Humans
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Infusions, Intravenous
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Insulin / administration & dosage
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Insulin / pharmacology*
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Muscle Fibers, Skeletal / cytology
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Muscle Fibers, Skeletal / physiology
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Muscle, Skeletal / cytology
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Muscle, Skeletal / enzymology
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Muscle, Skeletal / physiology*
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Obesity / enzymology
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Obesity / physiopathology*
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Phosphofructokinase-1 / metabolism
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Phosphorylases / metabolism
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Thinness
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Tomography, X-Ray Computed
Substances
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Blood Glucose
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Insulin
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3-Hydroxyacyl CoA Dehydrogenases
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Glyceraldehyde-3-Phosphate Dehydrogenases
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Electron Transport Complex IV
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Citrate (si)-Synthase
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Phosphorylases
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Hexokinase
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Phosphofructokinase-1
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Creatine Kinase
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Adenosine Triphosphatases
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Glucose