EFFECT OF ADMINISTRATION OF GNRH ANTAGONIST ON THE DEVELOPMENT OF CAPRINE CORPUS LUTEUM AND CLARIFICATION OF ITS MECHANISM

在研究的第一年，为了阐明黄体生成素在山羊黄体发育和维持中的作用，研究了GnRH拮抗剂对血液中黄体生成素和孕酮浓度的影响。结果表明，在山羊体内，黄体的发育和维持都需要内源性黄体，黄体的维持完全依赖于黄体，而黄体的早期发育较少依赖于黄体。在第二年的研究中，为了阐明黄体发育的机制，研究了黄体受体、血管内皮生长因子(VEGF)、CD34(内皮细胞的特异性标志物)、前列环素(PGI2)合成酶基因表达的变化。进一步研究GnRH拮抗剂对这些基因表达的影响，以探讨内源性黄体生成素对这些基因在山羊黄体中表达的影响。结果表明，在山羊黄体的发育过程中，内源性黄体生成素上调了黄体黄体中黄体黄体中的黄体黄体受体基因和蛋白的表达。在山羊黄体的维持期，其基因表达增强，而不是在黄体的发育期，因此可能有助于增强血管通透性。在山羊排卵后，PGI_2合成酶和代谢产物PGI_2的基因表达增加，可能是由于PGI_2促进了山羊黄体发育的早期阶段。此外，已有研究表明，血管内皮生长因子、CD34和PGI2合成酶的基因表达不受内源性黄体生成素的调节。

In the first year of the research project, to clarify the roles of luteinizing hormone (LH) in the development and maintenance of caprine corpus luteum, the effects of GnRH antagonist administration on concentrations of LH and progesterone in blood were examined. As the results, in the goat, it has been suggested that endogenous LH is required for both of the development and maintenance of corpus luteum, and that the corpus luteum is entirely dependent on LH for its maintenance but less dependent on LH for the early development of the corpus luteum.In the second year of the research project, to elucidate the mechanism of corpus luteum development, changes of gene expressions of LH receptor, vascular endothelial growth factor (VEGF), CD34 (a specific marker for endothelial cells), prostacyclin (PGI_2) synthase were examined. Furthermore, the effect of GnRH antagonist administration on those genes' expressions in order to examine the roles of endogenous LH for those genes' expressions in the caprine corpus luteum. As the results, it has been suggested that endogenous LH up-regulates the amounts of LH receptor mRNA and protein in the development of the caprine corpus lutuem. It is possible that VEGF_<165> could contribute enhancement of vascular permeability in the period of maintenace of the caprine corpus luteum, since its gene expression is enhanced in the period of maintenance rather than the period of development of the corpus luteum. It is likely that PGI_2 can stimulate the very eary phase of corpus luteum development in the goat, because gene expression of PGI_2 synthase and metabolite of PGI_2 are increased just after the ovulation. Moreover, it has been indicated that the gene expressions of VEGF, CD34 and PGI_2 synthase are regulated independently of endogenous LH.