Ovarian enzyme activities in women with polycystic ovary syndrome.

Studies using primary ovarian tissue and cultured human theca and granulosa cells have shown that steroidogenic enzyme activities are up-regulated in theca cells in polycystic ovary syndrome (PCOS). Although granulosa cells in arrested follicles in PCOS fail to express significant amounts of aromatase, there is an overexpression of 5alpha-reductase activity and premature expression of cholesterol side-chain cleavage cytochrome P450.