Miura Ryotaro
Department of Veterinary Medicine, Nippon Veterinary and Life Science University, Tokyo 180-8602, Japan.
J Reprod Dev. 2019 Aug 9;65(4):289-295. doi: 10.1262/jrd.2019-027. Epub 2019 May 13.
The first follicular wave emerges soon after ovulation, and its dominant follicle (DF) develops during the first 8-10 days of the estrous cycle in cattle. And, the first-wave DF is a non-ovulatory follicle, because it develops during the first half of the estrous cycle simultaneously with the corpus luteum (CL), which produces and secretes progesterone. Regarding the characteristics of development and the mechanisms of deviation in the DF during the follicular wave, the first-wave DF has been well studied. However, the characteristics of the first-wave DF, such as growth, blood flow in the follicular wall, concentration of sex steroid hormones in the peripheral blood and follicular fluid, amounts of mRNA in granulosa cells, as well as the characteristics of the CL formed after the first-wave DF and the influence of the first-wave DF on fertility (conception rate), have not been well studied. Additionally, the first-wave DF synthesizes and secretes 17β-estradiol (E), and plasma E concentration increases during the early stage of the estrous cycle. Consequently, there is a possibility that the first-wave DF might affect the fertility in cattle. In this review, to provide the new perspective on reproductive physiology in cattle, characteristics of the first-wave DF were examined in detail and its characteristics were compared with that of the second-wave DF. In addition, the locational effects of the first-wave DF and CL on conception rate are discussed.
第一个卵泡波在排卵后不久出现，其优势卵泡（DF）在牛发情周期的前8 - 10天发育。并且，第一波优势卵泡是一个不排卵的卵泡，因为它在发情周期的前半段与黄体（CL）同时发育，黄体会产生并分泌孕酮。关于卵泡波期间优势卵泡的发育特征和偏离机制，第一波优势卵泡已经得到了充分研究。然而，第一波优势卵泡的特征，如生长情况、卵泡壁血流、外周血和卵泡液中性类固醇激素浓度、颗粒细胞中mRNA的量，以及第一波优势卵泡形成后黄体的特征和第一波优势卵泡对繁殖力（受孕率）的影响，尚未得到充分研究。此外，第一波优势卵泡合成并分泌17β - 雌二醇（E），发情周期早期血浆E浓度会升高。因此，第一波优势卵泡有可能影响牛的繁殖力。在本综述中，为了提供关于牛生殖生理学的新视角，详细研究了第一波优势卵泡的特征，并将其与第二波优势卵泡的特征进行了比较。此外，还讨论了第一波优势卵泡和黄体对受孕率的位置效应。
