title: Role of reactive oxygen species in contraction-mediated glucose transport in mouse skeletal muscle.
abstract: Exercise increases glucose transport into skeletal muscle via a pathway that is poorly understood. We investigated the role of endogenously produced reactive oxygen species (ROS) in contraction-mediated glucose transport. Repeated contractions increased 2-deoxyglucose (2-DG) uptake roughly threefold in isolated, mouse extensor digitorum longus (fast-twitch) muscle. N-Acetylcysteine (NAC), a non-specific antioxidant, inhibited contraction-mediated 2-DG uptake by approximately 50% (P < 0.05 versus control values), but did not significantly affect basal 2-DG uptake or the uptake induced by insulin, hypoxia or 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR, which mimics AMP-mediated activation of AMP-activated protein kinase, AMPK). Ebselen, a glutathione peroxidase mimetic, also inhibited contraction-mediated 2-DG uptake (by almost 60%, P < 0.001 versus control values). Muscles from mice overexpressing Mn2+-dependent superoxide dismutase, which catalyses H2O2 production from superoxide anions, exhibited a approximately 25% higher rate of contraction-mediated 2-DG uptake versus muscles from wild-type control mice (P < 0.05). Exogenous H2O2 induced oxidative stress, as judged by an increase in the [GSSG]/[GSH + GSSG] (reduced glutathione + oxidized glutathione) ratio to 2.5 times control values, and this increase was substantially blocked by NAC. Similarly, NAC significantly attenuated contraction-mediated oxidative stress as judged by measurements of glutathione status and the intracellular ROS level with the fluorescent indicator 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein (P < 0.05). Finally, contraction increased AMPK activity and phosphorylation approximately 10-fold, and NAC blocked approximately 50% of these changes. These data indicate that endogenously produced ROS, possibly H2O2 or its derivatives, play an important role in contraction-mediated activation of glucose transport in fast-twitch muscle.
authors.affiliation: Department of Physiology and Pharmacology, Karolinska Institutet, 171 77 Stockholm, Sweden.
authors.forename: Marie E
authors.initials: ME
authors.lastname: Sandström
authors.forename: Shi-Jin
authors.initials: SJ
authors.lastname: Zhang
authors.forename: Joseph
authors.initials: J
authors.lastname: Bruton
authors.forename: José P
authors.initials: JP
authors.lastname: Silva
authors.forename: Michael B
authors.initials: MB
authors.lastname: Reid
authors.forename: Håkan
authors.initials: H
authors.lastname: Westerblad
authors.forename: Abram
authors.initials: A
authors.lastname: Katz
mesh_terms: D055372:AMP-Activated Protein Kinases; D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D003847:Deoxyglucose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009097:Multienzyme Complexes / Q000378:metabolism; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D018384:Oxidative Stress; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*; D000099156:Superoxide Dismutase 2
chemical_list: D055372:AMP-Activated Protein Kinases; D000111:Acetylcysteine; D000975:Antioxidants; D003847:Deoxyglucose; D005947:Glucose; D005978:Glutathione; D006861:Hydrogen Peroxide; D009097:Multienzyme Complexes; D017346:Protein Serine-Threonine Kinases; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase; D000099156:Superoxide Dismutase 2