CYP17A1 and polycystic ovary syndrome: Zhang et al. found that IL-18 increased the secretion of 17-OHP and androstenedione and upregulated the expression of critical steroidogenesis-related genes Cyp11a1 and CyP17A1, which may be the pathway for the mode of action of IL-18 in PCOS and also suggests that 17-OHP contributes to the pathogenesis of PCOS [37].