[Induction of insulin resistance induced by PI-3K inhibitor in porcine granulosa cells].

Objective To investigate the biological effects of insulin resistance(IR)on the porcine granulosa cells which iS induced by wortmannin,the PI-3K inhibitor and mediated by key molecules including GLUT4 and MAPK during insulin signaling.Methods The model of IR porcine granulosa cell was established in in vitro culture by treatment of wortmannin,and was assessed the amount of3H glucose uptake as well as medium glucose levels by glucose oxidase method.The protein and mRNA expression of GLUT4 and MAPK were evaluated by immunofluorescence and RT-PCR respectively.Resuits The glucose intake was decreased by 40% with treatment of wortmannin at 1.5 μmol/L(P＜0.05).GLUT4 and MAPK were localized mainly to cytoplasm of grantdose cells.When granulosa cells were insulin resistant,the expression of GLUT4 was down-regulated whereas MAPK was up-regulated as compared with the controls.Conclusions Wortmannin treatment can lcad to decreased expression of GLUT4 and increase of IR granulose cells.This metabolic phenotype could induce increased expression of MAPK and mitogenic potential,indicating the cross-talk between two pathways of insulin signaling within ovarian cells. Key words: Insulin resistance; 1-phosphatidylinositol 3-kinase; Androstadienes; Monosaccharide transport proteins; Mitogen-activated protein kinases