title: Mitochondrial respiratory capacity and content are normal in young insulin-resistant obese humans.
abstract: Considerable debate exists about whether alterations in mitochondrial respiratory capacity and/or content play a causal role in the development of insulin resistance during obesity. The current study was undertaken to determine whether such alterations are present during the initial stages of insulin resistance in humans. Young (∼23 years) insulin-sensitive lean and insulin-resistant obese men and women were studied. Insulin resistance was confirmed through an intravenous glucose tolerance test. Measures of mitochondrial respiratory capacity and content as well as H(2)O(2) emitting potential and the cellular redox environment were performed in permeabilized myofibers and primary myotubes prepared from vastus lateralis muscle biopsy specimens. No differences in mitochondrial respiratory function or content were observed between lean and obese subjects, despite elevations in H(2)O(2) emission rates and reductions in cellular glutathione. These findings were apparent in permeabilized myofibers as well as in primary myotubes. The results suggest that reductions in mitochondrial respiratory capacity and content are not required for the initial manifestation of peripheral insulin resistance.
authors: East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC.
authors: Kelsey H
authors: KH
authors: Fisher-Wellman
authors: Todd M
authors: TM
authors: Weber
authors: Brook L
authors: BL
authors: Cathey
authors: Patricia M
authors: PM
authors: Brophy
authors: Laura A A
authors: LA
authors: Gilliam
authors: Constance L
authors: CL
authors: Kane
authors: Jill M
authors: JM
authors: Maples
authors: Timothy P
authors: TP
authors: Gavin
authors: Joseph A
authors: JA
authors: Houmard
authors: P Darrell
authors: PD
authors: Neufer
mesh_terms: D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008931:Mitochondria, Muscle / Q000378:metabolism*; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism; D009765:Obesity / Q000378:metabolism*; D010084:Oxidation-Reduction
chemical_list: D001786:Blood Glucose; D007328:Insulin; D006861:Hydrogen Peroxide
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