CYP19A1 and polycystic ovary syndrome: One of the reasonsfor insufficient production of estradiol in PCOS folliclesis the inadequate amount of aromatase to stimulate bioactivityand increase aromatase mRNA expression (28).Takayama et al. (30) reported that immunohistochemicalstudies of polycystic ovaries did not show any aromataseactivity in antral follicles of various sizes (30).