title: [Adiponectin decreases insulin receptor substrate-1 phosphorylation in the liver of OLETF rats possibly through nuclear factor-κB signaling pathway].
abstract: OBJECTIVE
  To investigate the effect of adiponectin (APN) on the insulin pathway in the liver of OLETF rats and explore its molecular mechanism.
  
  
  METHODS
  Twenty male OLETF rats and 10 male LETO rats were sacrificed at 8 and 32 weeks of age to examine the fasting blood glucose, serum insulin, adiponectin and blood lipid profiles. The APN, phosphotyrosine of insulin receptor substrate-1 (IRS-1), IKKβ and nuclear-κB (NF-κB) in the liver tissue were determined using ELISA, Western blotting or immunohistochemistry.
  
  
  RESULTS
  The plasma adiponectin level in OLETF rats was significantly lower than that of LETO rats since 8 weeks of age (P<0.01). At 32 weeks of age, the blood lipid levels of OLETF rats increased significantly (P<0.05) with inverse correlations to plasma adiponectin (P<0.01). The liver APN, py-IRS-1, IKKβ and NF-κB levels in OLETF rats differed significantly from those of LETO rats at both 8 and 32 weeks. At 32 weeks of age, the APN level of both rats were correlated to the levels of NF-κB and py-IRS-1 (P<0.01).
  
  
  CONCLUSIONS
  APN may decrease tyrosine phosphorylation of IRS-1 via the IKK/NFκB pathway and inhibit insulin signaling pathway in the liver, which contributes to hyperlipidemia, hyperglycemia and development of type 2 diabetes.
authors: Department of Endocrinology and Metabolism, Southern Medical University, Guangzhou , China. bozhudr@gmail.com
authors: Bo
authors: B
authors: Zhu
authors: Chen-zhong
authors: CZ
authors: Li
authors: Yi
authors: Y
authors: Qian
authors: Yong-hua
authors: YH
authors: Pan
authors: Jia
authors: J
authors: Li
authors: Yan
authors: Y
authors: Zhang
authors: Yao-ming
authors: YM
authors: Xue