Résumé
OBJECTIVE To investigate the role of gonadotropin-releasing hormone (GnRH) in es-tradiol(E2 ) induced advance of puberty onset in rats. METHODS Postnatal day 18 SD rats were given a daily intragastric administration of corn oil or E2(50 μg.kg-1 ) for consecutive 5 d. The day of vaginal opening (VO), pathological changes in ovary and protein expression levels of GnRH, G protein-coupled receptor 54 ( GPR54) and phospholipase C ( PLC) in hypothalamus were observed. RESULTS As compared to corn oil controll group, VO was advanced by about 12.2 d, corpus luteum was observed in the ovary section, and the protein expression levels of GnRH,GPR54 and PLC in hypothalamus were significantly increased by 47%, 55% and 56% in E2 group, respectively. CONCLUSION E2 induced onset of puberty advance may be closely related to regulation of the expression of GnRH, GPR54 and PLC in hypothalamus.