CYP17A1 and polycystic ovary syndrome: Insulin resistance is observed in 50–90% of PCOS patients, leading to hyperinsulinemia.[45] Hyperinsulinemia intensifies LH pulses, stimulates adrenal CYP17A1 activity, and reduces hepatic production of SHBG.[46] These conditions act synergistically on ovarian theca cells, activating CYP17A1 and increasing circulating androgens.