CYP17A1 and polycystic ovary syndrome: Furthermore, inhibition of GnRH can decrease the level of testosterone; regulation of PI3K/Akt in decreasing the expression of CYP17A1 avoids the conversion of pregnenolone to DHEA; and downregulation of FSH inhibits the combination between FSH and the FSH receptor to reduce cAMP through the PKA pathway for downregulating aromatase, showing potential therapeutic effects on PCOS.