McNatty K P, Juengel J L, Wilson T, Galloway S M, Davis G H, Hudson N L, Moeller C L, Cranfield M, Reader K L, Laitinen M P E, Groome N P, Sawyer H R, Ritvos O
AgResearch, Wallaceville Animal Research Centre, PO Box 40063, Upper Hutt, New Zealand.
Reprod Suppl. 2003;61:339-51.
The physiological mechanisms controlling ovulation rate in mammals involve a complex exchange of endocrine signals between the pituitary gland and the ovary, and a localized exchange of intraovarian hormones between the oocyte and its adjacent somatic cells. The discoveries in sheep of mutations in bone morphogenetic protein 15 (BMP15) and bone morphogenetic protein receptor type IB (BMPR-IB) together with recent findings on the physiological effects of growth differentiation factor 9 (GDF9) and BMP15 on follicular development and ovulation rate highlight some important differences in the way in which the oocyte may function in mammals with different ovulation rate phenotypes. In sheep, BMP15 and GDF9 have each been shown to be essential for the early and later stages of follicular development. In addition, ovulation rate is sensitive to changes in the dose of either of these two oocyte-derived growth factors. These findings are in contrast to those reported for mice in which GDF9, but not BMP15, is essential for follicular development. The evidence to date is consistent with the hypothesis that the oocyte plays a central role in regulating key events in the process of follicular development and hence, is important in determining ovulation rate. Moreover, it appears that the mechanisms that the oocyte uses to control these processes differ between species with low and high ovulation rate phenotypes.
哺乳动物中控制排卵率的生理机制涉及垂体与卵巢之间复杂的内分泌信号交换，以及卵母细胞与其相邻体细胞之间局部的卵巢内激素交换。在绵羊中发现骨形态发生蛋白15（BMP15）和骨形态发生蛋白受体IB型（BMPR - IB）的突变，以及最近关于生长分化因子9（GDF9）和BMP15对卵泡发育和排卵率生理影响的研究结果，凸显了卵母细胞在具有不同排卵率表型的哺乳动物中发挥作用方式的一些重要差异。在绵羊中，BMP15和GDF9已被证明对卵泡发育的早期和后期阶段均至关重要。此外，排卵率对这两种卵母细胞衍生生长因子中任何一种剂量的变化都很敏感。这些发现与小鼠的情况形成对比，在小鼠中，GDF9对卵泡发育至关重要，而BMP15并非如此。迄今为止的证据与以下假设一致，即卵母细胞在调节卵泡发育过程中的关键事件中起核心作用，因此在确定排卵率方面很重要。此外，卵母细胞用于控制这些过程的机制似乎在排卵率表型低和高的物种之间有所不同。
