Polycystic ovary syndrome (PCOS) patients have intra-ovarian hyperandrogenism and granulosa cells (GCs) from PCOS patients have impaired insulin-dependent glucose metabolism and insulin resistance. The purpose of this study is to determine whether excess androgen affects glucose metabolism and induces insulin resistance of GCs. We firstly explored the insulin metabolic signaling pathway and glucose metabolism in cultured GCs. The Akt phosphorylation and lactate production were increased after insulin treatment. Pre-treatment with PI3-K inhibitor attenuated insulin-induced phosphorylation of Akt and lactate accumulation. However, after treating GCs with different concentrations of testosterone for 5 days, insulin-induced phosphorylation of Akt and lactate production showed no significant change comparing with those of control cells. Finally, mRNA expression of insulin signaling mediators including INSR, IRS-1, IRS-2, and GLUT-4 in GCs was also not significantly altered after testosterone treatment. In conclusion, insulin activates PI3-K/Akt signaling pathway and promotes lactate production in ovarian GCs, but high androgen exerted no obvious influence on insulin signaling pathway and metabolic effect in GCs, suggesting that metabolic actions of insulin in ovarian GCs were unaffected by hyperandrogenism directly.
Keywords: Granulosa cell; High androgen; Insulin resistance; Polycystic ovary syndrome.