Campbell B K, Baird D T, Souza C J H, Webb R
School of Human Development, University of Nottingham, Floor D East Block, Queen's Medical Centre, Nottingham NG7 2UH, UK.
Reproduction. 2003 Jul;126(1):101-11. doi: 10.1530/rep.0.1260101.
The aim of this study was to differentiate between pituitary and ovarian actions of the FecB gene by measuring the ovarian response to a standardized treatment with gonadotrophins designed to mimic the changes in FSH and LH that occur in the follicular phase of the ovarian cycle in ewes, with (Fec(B/-), n=6) and without (Fec(+/+), n=9) the gene, that were rendered hypogonadotrophic by pretreatment with a potent antagonist of GnRH. Ewes with ovarian autotransplants were used to facilitate the assessment of follicular function by the collection of ovarian venous blood and ultrasonography. The gonadotrophin regimen resulted in concentrations of FSH and LH that were similar to concentrations found in a normal cycle and did not differ between genotypes. Follicular development and ovulation occurred in all animals, and patterns of secretion of oestradiol, androstenedione and inhibin A were normal. Despite these endocrine similarities, the antral follicle population stimulated by FSH infusion retained the characteristic genotypic difference with the ovaries of Fec(+/+) animals containing a range of follicle sizes with decreasing proportions of small (<3.5 mm in diameter) and medium (3.5-4.5 mm in diameter) follicles as well as large follicles (> or =4.5 mm in diameter), whereas the ovaries of Fec(B/-) ewes contained no follicles of >4.5 mm in diameter. This genotypic difference was retained after ovulation with gene carriers having more preovulatory follicles/corpora lutea (3.8+/-0.3) of a smaller diameter (5.3+/-0.3 mm) than did non-gene carriers (1.7+/-0.3; 11.4+/-0.9 mm; P<0.05). As ewes carrying the FecB gene mutation were able to ovulate more follicles than non-gene carriers, despite identical concentrations and patterns of FSH and LH stimulation, the results of this study support the hypothesis that the FecB gene acts at the ovary to enhance ovarian sensitivity to gonadotrophic stimulation.
本研究的目的是通过测量携带（Fec(B/-)，n = 6）和不携带（Fec(+/+)，n = 9）该基因的母羊对促性腺激素标准化治疗的卵巢反应来区分FecB基因在垂体和卵巢的作用。这些母羊通过用GnRH强效拮抗剂预处理而导致性腺功能减退。使用具有卵巢自体移植的母羊，通过收集卵巢静脉血和超声检查来促进对卵泡功能的评估。促性腺激素治疗方案导致的FSH和LH浓度与正常周期中的浓度相似，且在不同基因型之间没有差异。所有动物均发生卵泡发育和排卵，雌二醇、雄烯二酮和抑制素A的分泌模式正常。尽管存在这些内分泌方面的相似性，但FSH输注刺激的窦卵泡群体仍保留了特征性的基因型差异，Fec(+/+)动物的卵巢含有一系列大小的卵泡，其中小卵泡（直径<3.5 mm）和中卵泡（直径3.5 - 4.5 mm）以及大卵泡（直径≥4.5 mm）的比例逐渐降低，而Fec(B/-)母羊的卵巢中没有直径>4.5 mm的卵泡。排卵后这种基因型差异仍然存在，基因携带者的排卵前卵泡/黄体数量（3.8±0.3）比非基因携带者更多（1.7±0.3），但直径更小（5.3±0.3 mm，而非11.4±0.9 mm；P<0.05）。由于携带FecB基因突变的母羊尽管FSH和LH刺激的浓度和模式相同，但能够排卵更多卵泡，因此本研究结果支持以下假设：FecB基因在卵巢起作用，增强卵巢对促性腺激素刺激的敏感性。
