Introduction: Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women of reproductive age. Increased GnRH/luteinizing hormone (LH) pulse frequency is a characteristic of endocrine abnormalities in PCOS. Kisspeptin antagonists reduce LH pulse frequency and amplitude and are hence supposed to slow GnRH neuron activity that may adjust GnRH/LH levels in PCOS conditions. Objective:To investigate the impact of kisspeptin antagonist P271 administration during prenatal life to reduce GnRH expression in adulthood in prenatally androgenized (PNA) rats as a model of PCOS. Materials and methods:PNA rats (n=9) and controls (n=9) received P271 on day 20 of their prenatal life, and they were examined in adulthood (110-120 days). The ability of P271 to alter GnRH mRNA expression, and plasma levels of gonadotropins and steroid hormones were tested using reverse transcription q-Real-time PCR and ELISA methods, respectively. Results:In this study, based on the result of Generalized Estimating Equation (GEE) model, we found that GnRH expression in PCOS+P271 rats decreased compared to PCOS rats in the diestrous phase. In addition, P271 administration reduced gonadal steroid and gonadotropin levels in both PCOS and non-PCOS rats.