Polycystic ovary syndrome (PCOS) is a female endocrine disorder and is characterized by anovulation, menstrual irregularity and condition of androgen excess. Kisspeptin is implicated in ovulation and follicular development by stimulation of GnRH/luteinizing hormone (LH) secretion. The purpose of this study was to determine whether chronic exposure to androgen affects expression of kisspeptin and LH release in female rats, because women with PCOS show hyperandrogenism. Weaned female rats were implanted subcutaneously with 90-days continuous-release pellets of 5a-dihydrotestosterone (DHT), and were used after 10 wk of age. Kiss1 mRNA-expressing cells in both the anteroventral periventricular nucleus (AVPV) and arcuate nucleus (ARC) were significantly decreased in DHT-implanted group. AVPV kisspeptin neurons are known to be involved in LH surge generation and are positively regulated by estrogen. DHT animals could not detect estradiol (E2)-induced LH surge, while there were no significant differences in numbers of AVPV Kiss1 cells, kisspeptin-immunoreactive (ir) cells and GnRH-ir cells between both groups in the presence of high E2. ARC kisspeptin neurons are considered to participate in pulsatile LH release and are a target of estrogen-negative feedback action. ARC Kiss1 cells were significantly decreased in ovariectomized (OVX) DHT rats compared to OVX rats. Pulsatile LH secretion was suppressed in OVX DHT rats. Central injection of kisspeptin-10 or intravenous injection of GnRH agonist did not affect LH release in DHT animals. These results suggest that hyperandrogenism may suppress LH surge and pulsatile LH secretion through decreasing responsiveness to GnRH in the pituitary and inhibition of ARC kisspeptin expression. On the other hand, AVPV kisspeptin neurons may be unaffected by androgen. Hence, hyperandrogenism in PCOS may be associated with anovulation and menstrual irregularity by adversely affecting ARC kisspeptin neurons and the pituitary.