ABSTRACT
AIM:To investigate the effect of insulin on vascular smooth muscle cells (VSMCs) proliferation and to evaluate the intracellular signaling pathways involved.METHODS:VSMCs separated from Sprague-Dawley rats were used in this study. The proliferation of VSMCs induced by insulin was assayed by [3H]-thymidin incorporation. The protein expression and activity of p-ERK1/2 were determined by immunblot and [?-32P]ATP incorporation.RESULTS:Insulin induced cell proliferation in a concentration-dependent manner. The proliferative effect of insulin on VSMCs was inhibited partly by LY294002 (48.8%),an inhibitor of PI-3 kinase,and the ERK1/2 inhibitor PD98059 (43.6%),respectively. Moreover,phosphorylation of ERK1/2 and activity of ERK1/2 induced by insulin were also inhibited partly by LY294002.CONCLUSION:PI-3 kinase and ERK1/2 are involved in insulin induced VSMCs proliferation.