In vitro studies have shown that the treatment of GCs from the preovulatory follicles of lean women with PCOS with DHT leads to the down-regulation of aquaporin 9 expression via the PI3K pathway [154], suggesting that hyperandrogenism in PCOS further impairs aquaporin function, thereby compromising follicular maturation. This evidence concerns the gene AQP9 and polycystic ovary syndrome.