In rat ovaries, NGF is principally synthesized in the cells of the follicular wall (Dissen et al., 1996), and in PCOS, the activation of NGF may be a factor involved in enhancing norepinephrine outflow to the gland, which is induced by estradiol valerate (EV) (Lara et al., 2000) PCOS exhibits a high intraovarian nerve fiber density that is associated with sympathetic hyperresponsiveness (Stener-Victorin et al., 2003). This evidence concerns the gene NGF and polycystic ovary syndrome.