It has recently been shown that kisspeptin plays a critical role in the central regulation of the hypothalamo-pituitary gonadal axis in both male and female (Smith et al. 2006). It potently stimulates luteinising hormone (LH) release from the anterior pituitary, and this effect appears to be mediated via the hypothalamic gonadotrophin releasing hormone (GnRH) system. We have investigated effects of kisspeptin on serum LH and follicle stimulating hormone (FSH) levels and concomitant hypothalamic noradrenaline concentrations in pro-oestrous rats. In addition, an α-1 adrenergic receptor antagonist (prazosin) was used to challenge kisspeptin by blockade of the central noradrenergic neurotransmission. Adult female Sprague-Dawley rats were used in this study. Daily vaginal smear was performed, and only pro-oestrous animals were chosen for experimentation. Pro-oestrous rats were intraperitoneally injected with kisspeptin-10 (50 nM/kg), prazosin (2 mg/kg) or prazosin + kisspeptin at 14.00h. Controls received saline alone. All animals were decapitated at 15.00h and blood samples obtained. The brains were rapidly removed and frozen on dry ice. Medial preoptic area (MPOA), arcuate nucleus (ARN) and median eminence (ME) were surgically isolated by micropunch technique. Concentrations of noradrenaline in these samples were determined by high performance liquid chromatography with electrochemical detection. Protein content in the hypothalamic samples was measured by spectrophotometry, and the results were expressed as pg amine/μg protein. Serum LH levels were measured by enzyme immunoassay. This study was approved by the local ethics committee. Mann-Whitney U test was utilized for statistical analysis of the data. Kisspeptin significantly increased noradrenaline content in the hypothalamic areas examined (p<0.05). Although prazosin lowered noradrenaline levels, these changes were significant in only the ARN (p<0.05). Co-administration of kisspeptin with prazosin resulted in increased noradrenaline concentrations in the MPOA and ARN. Kisspeptin caused a significant increase in serum LH and FSH levels (p0.05). Combination of kisspeptin with prazosin elevated serum LH levels compared to prazosin-treated group (p<0.05). These findings suggest that kisspeptin stimulates both LH and FSH in the pro-oestrous rat. This is the first attempt to show that stimulatory effect of kisspeptin on GnRH and thus gonadotropin release may involve increased noradrenergic activity in the hypothalamus.