The Effect And Mechanism Of Kisspeptin/GPR54on Endocrine Function Of Rat Luteal Cells

Objectives:The study aims to explore the expression of kisspeptin/GPR54in the rat ovary, and observe the effect and mechanism of kisspeptin/GPR54on endocrine function of rat luteal cells in vitro.Methods:1. To observe the expression and localization of kisspeptin and GPR54in rat ovarian tissues by immunohistochemistry, real-time quantitative PCR and Western blot method.2. To observe the effect of kisspeptin on the basal and hCG stimulated progesterone secretion in the rat luteal cells in vitro by radioimmunoassay.3. To explore the possible signaling pathway of kisspeptin on the progesterone secretion of basic and hCG-induced rat luteal cell by Western blot method.Results:1. Using real-time PCR, we found that levels of ovarian KiSS-1mRNA significantly increased in gonadotropin-primed immature rats, with a peak at7d after hCG treatment.2. Immunostaining examination showed that, before gonadotropin treatment, kisspeptin and GPR54protein were weakly stained in granulosa cells of primary follicle; following gonadotropin treatment, kisspeptin were strongly localized in the theca cells, interstitial compartment and corpora lutea, and GPR54protein was obviously detected in the corpus luteum of rat ovaries.3. In cultured luteal cells, kisspeptin-10treatment augmented basal and hCG stimulated progesterone but not estradiol production, with concomitant increases in transcript levels for key steroidogenic enzymes (StAR, CYP11A, and3β-HSD).4. Furthermore, treatment with kisspeptin-10increased the phosphorylation of Erkl/2mitogen-activated protein kinase in cultured luteal cells. Moreover, inhibiting the Erkl/2pathways with PD98059prevented kisspeptin induced progesterone secretion.Conclusion:Kisspeptin/GPR54directly regulates progesterone secretion via the Erkl/2mitogen-activated protein kinase signaling pathway in rat luteal cells...