The distribution of GHS-R1a in hypothalamus-pituitary-ovarian axis were detected by PV-9000 two-step immunohistochemical.Real-time quantitative PCR was used to detect expression of GHS-R1a mRNA during estrous cycle.The results showed that GHS-R1a were mainly distributed in hypothalamus of the arcuate nucleus,ventromedial nucleus,median eminence,the chromophil cells of anterior pituitary,luteal cells,hilus interstitial cells,and oocyte.GHS-R1a mRNA were expressed in hypothalamus and pituitary of rats throughout the estrous cycle and regulated by estrous cycle.GHS-R1a mRNA was not observed in ovary of rats.