title: [Effect of IGF-1 on PI3K/PTEN signal pathway in vascular smooth muscle cell].
abstract: OBJECTIVE
  To investigate the cellular signal transduction pathway of vascular smooth muscle cell (VSMC) proliferation stimulated by insulin-like growth factor-1 (IGF-1).
  
  
  METHODS
  Rabbit aortic VSMCs was cultured in 3 groups. Cell proliferating ability was determined by measuring cell number and mitochondrial dehydrogenase (MD) activity (MTT assay). Wortmannin (WT), the specific inhibitor of phosphatidylinositol 3-kinase (PI3K), was used to evaluate indirectly the possible involvement of PI3K. Western blotting was used to detect the protein expression of phosphatase PTEN. Diphosphate action of PTEN on its specific substrate diC16PIP3 was measured by green reagent method.
  
  
  RESULTS
  IGF-1 (100 microg/L) increased cell number and MD activity by 2.8-3.8 fold. WT markedly inhibited VSMC proliferation and completely abolished the above effects of IGF-1. IGF-1 inhibited PTEN activity in a concentration-(10-100 microg/L) and time--(3 min-24 h) dependent manner (P < 0.01).
  
  
  CONCLUSIONS
  IGF-1 increases VSM proliferation by increasing PI3K activity and inhibiting PTEN activity.
authors.affiliation: Institute of Geriatric Cardiology, PLA General Hospital, Beijing 100853, China.
authors.forename: Xing-li
authors.initials: XL
authors.lastname: Wu
authors.forename: Ding-you
authors.initials: DY
authors.lastname: Yang
authors.forename: Zhong-su
authors.initials: ZS
authors.lastname: Yang
authors.forename: Shi-wen
authors.initials: SW
authors.lastname: Wang
authors.forename: Yu-sheng
authors.initials: YS
authors.lastname: Zhao
mesh_terms: D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects*; D051059:PTEN Phosphohydrolase / Q000378:metabolism*; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism*; D010766:Phosphorylation; D011817:Rabbits; D015398:Signal Transduction
chemical_list: D007334:Insulin-Like Growth Factor I; D058539:Phosphatidylinositol 3-Kinase; D051059:PTEN Phosphohydrolase