NGF and polycystic ovary syndrome: Hyperandrogenism plays a key role in the pathogenesis of PCOS and several PCOS-like mouse models have applied excessive androgen at different developmental time windows including the prenatal androgenization (PNA) and the peripubertal androgenization models together with the transgenic 17NF model overexpressing nerve growth factor (NGF) in the ovarian theca cells13,17–21.