Souza C J, Campbell B K, Baird D T
Department of Obstetrics and Gynaecology, University of Edinburgh, UK.
J Reprod Fertil. 1996 Sep;108(1):101-6. doi: 10.1530/jrf.0.1080101.
The dynamics of ovarian follicular development and its relationship to ovarian and pituitary hormones during seasonal anoestrus were investigated for 10 days in nine ewes with autotransplanted ovaries in a longitudinal study. The size and position in the ovary of individual follicles over 2.5 mm in diameter were recorded by daily ultrasonography. Samples of ovarian and jugular venous blood were collected at intervals of 12 h, before and after a GnRH challenge (2.50 ng GnRH, i.v.) so that basal and LH-stimulated ovarian steroid secretion could be determined. Throughout the experimental period, all animals developed at least one large antral follicle > 5 mm, which secreted increased (P < 0.05) amounts of oestradiol and androstenedione in response to an LH challenge as the diameter of the follicle increased. However, a decrease (P < 0.05) in ovarian steroid secretion preceded any significant change in follicular diameter, indicating a dissociation between morphological and functional stages of dominance in sheep. We conclude that follicular growth and ovarian steroid secretion in sheep occur in wave-like forms, with the ascending and static part of both waves being synchronous but with a decline in steroid secretion preceding any changes in follicular diameter. Therefore, in sheep, follicular size alone is not an adequate parameter to assign dominance, and the secretory status of the follicle at any given time must be taken into account when studying the dynamics of follicular growth.
在一项纵向研究中，对9只自体移植卵巢的母羊进行了为期10天的研究，以探讨季节性乏情期间卵泡发育的动态变化及其与卵巢和垂体激素的关系。通过每日超声检查记录直径超过2.5毫米的单个卵泡在卵巢中的大小和位置。在GnRH刺激（静脉注射2.50纳克GnRH）前后，每隔12小时采集卵巢和颈静脉血样本，以便测定基础和LH刺激后的卵巢类固醇分泌。在整个实验期间，所有动物至少发育出一个直径大于5毫米的大型卵泡，随着卵泡直径的增加，该卵泡对LH刺激的反应分泌的雌二醇和雄烯二酮量增加（P<0.05）。然而，在卵泡直径发生任何显著变化之前，卵巢类固醇分泌就出现了下降（P<0.05），这表明绵羊优势卵泡的形态和功能阶段之间存在分离。我们得出结论，绵羊的卵泡生长和卵巢类固醇分泌呈波浪状形式，两个波浪的上升和静止部分是同步的，但类固醇分泌的下降先于卵泡直径的任何变化。因此，在绵羊中，仅卵泡大小并不是确定优势卵泡的充分参数，在研究卵泡生长动态时，必须考虑任何给定时间卵泡的分泌状态
