title: Role of oxidative stress in hypertrophied myoblasts stimulated by isoproterenol.
abstract: OBJECTIVE
  Hydrogen peroxide (H(2)O(2)), one of the oxyradical members, has been shown to have insulin-like effects, and endogenous H(2)O(2) may have the ability to improve impaired glucose metabolism. As a mechanism contributing to progression of hypertrophy, we hypothesized that the formation of H(2)O(2) to improve glucose uptake could be an oxidative stress resulting in apoptotic cell death.
  
  
  METHODS
  We used cultured myoblasts (H9c2) stimulated by isoproterenol as a model to focus on glucose metabolism, oxidative stress, apoptosis, and extracellular signal-regulated protein kinases (ERKs) expression.
  
  
  RESULTS
  In hypertrophied myoblasts, anaerobic glycolysis became prominent at day 7 of isoproterenol stimulation (ISO7; isoproterenol was administered for 7 days). Hydroperoxides production started to increase at day 5 of isoproterenol stimulation (ISO5) and peaked at ISO7. Apoptotic cell death was significantly increased in ISO5 and ISO7. Temporary ERKs suppression was also found at ISO5 and ISO7. Change in glucose metabolism led to stimulation of hydroperoxides production, apoptotic cell death and suppression of ERKs.
  
  
  CONCLUSIONS
  We concluded that oxidative stress was increased during the progression of hypertrophied myoblasts in association with impaired glucose metabolism and increased apoptotic cell death. Suppression of ERKs may be involved in signal transduction of apoptotic cell death.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Itoh
authors.forename: Masahito
authors.initials: M
authors.lastname: Minakawa
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ono
authors.forename: Takao
authors.initials: T
authors.lastname: Tsushima
authors.forename: Kozo
authors.initials: K
authors.lastname: Fukui
authors.forename: Ikuo
authors.initials: I
authors.lastname: Fukuda
mesh_terms: D000818:Animals; D017209:Apoptosis; D006332:Cardiomegaly / Q000378:metabolism; D002478:Cells, Cultured; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D006984:Hypertrophy; D007545:Isoproterenol; D019344:Lactic Acid / Q000378:metabolism; D032386:Myoblasts, Cardiac / Q000378:metabolism* / Q000473:pathology; D018384:Oxidative Stress; D051381:Rats
chemical_list: D019344:Lactic Acid; D006861:Hydrogen Peroxide; D048049:Extracellular Signal-Regulated MAP Kinases; D005947:Glucose; D007545:Isoproterenol