title: [Effect of acetyl-L-carnitine on the insulin resistance of L6 cells induced by tumor necrosis factor-alpha].
abstract: OBJECTIVE
  To investigate the effects of acetyl-L-carnitine (ALC) on the insulin resistance of rat L6 cells induced by tumor necrosis factor-alpha (TNF-alpha).
  
  
  METHODS
  Well-differentiated rat L6 muscle cells were divided into 6 groups, including control group, insulin (100 nmol/L) group, insulin (100 nmol/L) + TNF-alpha (10 ng/ml) group, and three insulin + TNF-alpha + ALC (0.1, 0.3 and 0.6 mmol/L respectively) groups. The glucose remained in culture medium was measured by the method of glucose oxidizes peroxides (GOD-POD). The glucose uptake of L6 cells was tested by [3H]-2-deoxyglucose. The expression of insulin receptor substrate-1 (IRS-1) was examined by western blotting.
  
  
  RESULTS
  The glucose content remained in culture medium was increased by TNF-alpha and the glucose uptake of cells was inhibited by TNF-alpha. The inhibition of TNF-alpha could be improved by ALC and in a dose-response relation. Compared with the insulin group, the expression of Ser307 phosphorylation of IRS-1 was lower in TNF-alpha group, and the expression of Ser307 phosphorylation of IRS-1 was decreased by ALC.
  
  
  CONCLUSIONS
  The insulin resistance in L6 cells induced by TNF-alpha might be attenuated by ALC via decreasing the expression of Ser307 phosphorylation of IRS-1.
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Peking University, Beijing 100191, China.
authors.forename: Zhaofeng
authors.initials: Z
authors.lastname: Zhang
authors.forename: Ming
authors.initials: M
authors.lastname: Zhao
authors.forename: Junbo
authors.initials: J
authors.lastname: Wang
authors.forename: Ye
authors.initials: Y
authors.lastname: Ding
authors.forename: Xiaoqian
authors.initials: X
authors.lastname: Dai
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
mesh_terms: D000108:Acetylcarnitine / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D004195:Disease Models, Animal; D055504:Insulin Receptor Substrate Proteins / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology*; D032342:Muscle Cells / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D055504:Insulin Receptor Substrate Proteins; C526296:Irs1 protein, rat; D014409:Tumor Necrosis Factor-alpha; D000108:Acetylcarnitine