Development of Technology for Regulating Reproductive Efficiency by Controlling Corpus Luteum Function in Cows

卵巢功能受血管功能控制，包括排卵、黄体发育和消退等局部现象。本研究旨在通过维持奶牛体内较高的孕酮水平，开发一种基础的和适用的技术来激活子宫内膜血管生成和功能，从而提高受孕率。同时，通过微透析系统的局部分泌和局部血流，通过彩色多普勒超声观察排卵卵泡和CL在发育和消退过程中的详细体内检查。从这一系列的实验中，第一次明确了以下几点。黄体生成素激增激活局部PG和血管活性肽的分泌复合物，诱导排卵前卵泡壁内局部血流量急剧增加，但闭锁卵泡内没有。这些变化是排卵的基本过程。因此，我们提出在排卵前卵泡中存在内皮素-血管紧张素- anp系统。排卵后立即发生的血管生成活跃与CL的形成及其功能（孕酮分泌）直接相关，这种局部机制涉及PG、血管紧张素和ANP的分泌功能，而不涉及内皮素。特别是，在发育中的CL中产生的促黄体因子PGF2α发挥促黄体而不是促黄体的作用。这一独特的机制可能与发育中的cl3的抗黄体溶解特性直接相关。一旦CL成熟，PGF2α可以诱导黄体溶解，而其他血管活性肽如内皮素和血管紧张素高度活跃并具有黄体溶解作用。这种局部机制导致CL内局部血流受到严重抑制，从而进一步加速了黄体溶解的级联反应。在奶牛排卵一天后单次注射hCG，可以有效地激活CL的形成以及血浆黄体酮水平，可能是通过促进CL中的血管生成。为了确认该处理对人工授精和胚胎移植后受孕率的影响，实地研究也在进行中。少

The ovarian function is controlled by vascular functions in various local phenomena including ovulation, corpus luteum (CL) development and regression. This study was conducted to develop a basic as well as applicable technology to activate CL angiogenesis and function thereby improving the conception rate by keeping high progesterone level in the cow. At the same time, a local secretion by a microdialysis system together with a local blood flow by a color Doppler ultrasonography observation of ovulatory follicle and CL during development and regression was examined in detail in vivo. From the series of experiments, the following points were clarified for the first time.1. A LH surge activates a complex of local secretion of PG and vasoactive peptides that induces an acute increase in the local blood flow within the preovulatory follicular wall, but not within the atretic follicles. These changes are essential process to ovulation. Consequently, we proposed the existence of endothelin- … More angiotensin-ANP system in the preovulatory follicles.2. The active angiogenesis occurring immediately after ovulation directly relates to the formation of CL and its function (progesterone secretion), and this local mechanism involves secretory function of PG, angiotensin and ANP, but not for endothelin. Particularly, a luteolytic factor PGF2α produced in the developing CL play a role as a luteotropic rather than luteolytic factor. This unique mechanism may directly correlate with anti-luteolytic characteristic of developing CL.3. Once the CL matures, PGF2α can induce luteolysis in which other vasoactive peptides such as endothelin and angiotensin are highly active and luteolytic. This local mechanism induces a serious inhibition of local blood flow within the CL so that a cascade of luteolysis is accelerated further.4. A single injection of hCG to the cow one day after ovulation effectively activates the CL formation as well as plasma progesterone level, possible by promoting angiogenesis in the CL. To confirm the impact of this treatment on the conception rate after artificial insemination and embryo transfer, the field studies are also on going. Less