BACKGROUND The antral follicle count (AFC) in mammalian ovaries positively correlates with female fertility. To clarify the causes of differences in fertility between low and high AFC cows, we investigated follicular growth dynamics and hormone concentrations in plasma, follicular fluid, and in vitro growth (IVG) media at different stages of follicular growth. METHODS Seven cows were divided into high AFC (n = 4, > 30 follicles) and low AFC (n = 3, < 30 follicles) groups based on the peak AFC detected by ultrasonography. These cows were subjected to estrous synchronization, daily ovarian ultrasonography, and blood collection. Their follicular fluid was collected from dominant follicles at different stages (selection, luteal, and ovulatory phases). In another experiment, we cultured oocyte-cumulus-granulosa cell complexes collected from early antral follicles (< 1 mm) for 12 days. Estradiol-17β (E2), testosterone (T), progesterone (P4), and anti-Müllerian hormone (AMH) concentrations in follicular fluids and plasma were measured. Plasma follicle-stimulating hormone (FSH) concentrations were examined. E2, P4, and AMH concentrations were also measured in IVG media. RESULTS The numbers of small (< 4 mm) and intermediate (4-8 mm) follicles were larger in the high AFC group than in the low AFC group (P < 0.05). The number of intermediate follicles was stable in the low AFC group, indicating consistent development. However, the number of these follicles fluctuated in the high AFC group. Plasma FSH concentrations were higher, whereas E2 and T concentrations were lower in the low AFC group (P < 0.05). E2 concentrations and the E2/P4 ratio in ovulatory follicles and IVG media on day 8 were higher in the high AFC group (P < 0.05). AMH concentrations in plasma and IVG media (P < 0.01) were higher in the high AFC group. CONCLUSIONS The weaker response to FSH of granulosa cells caused low E2 production in the low AFC group, resulting in high FSH concentrations and the consistent development of intermediate follicles. Conversely, higher E2 concentrations suppressed FSH secretion in the high AFC group. Granulosa cells in the high AFC group had the ability to produce more AMH than those in the low AFC group throughout IVG culture.

中文翻译：

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牛卵泡生长过程中肛门卵泡计数，类固醇生成以及促卵泡激素和抗苗勒管激素分泌之间的关系。

背景技术哺乳动物卵巢中的窦房卵泡计数（AFC）与女性生育力正相关。为了弄清低和高AFC奶牛之间生育力差异的原因，我们调查了在卵泡生长不同阶段的血浆，卵泡液和体外生长（IVG）培养基中的卵泡生长动力学和激素浓度。方法根据超声检查发现的AFC峰值，将7头奶牛分为高AFC组（n = 4，> 30个卵泡）和低AFC（n = 3，<30）。对这些母牛进行动情同步，每日卵巢超声检查和采血。从不同阶段（选择期，黄体期和排卵期）的优势卵泡中收集他们的卵泡液。在另一个实验中 我们培养了从早期肛门窦卵泡（<1 mm）收集的卵母细胞-卵丘-颗粒细胞复合物，共培养了12天。测量了卵泡液和血浆中的雌二醇17β（E2），睾丸激素（T），孕酮（P4）和抗苗勒氏激素（AMH）浓度。检查血浆卵泡刺激素（FSH）浓度。E2，P4和AMH浓度也在IVG培养基中测量。结果高AFC组的小卵泡（<4 mm）和中卵泡（4-8 mm）的数量大于低AFC组（P <0.05）。在低AFC组中，中间卵泡的数量是稳定的，表明发育稳定。然而，这些卵泡的数量在高AFC组中波动。在低AFC组中，血浆FSH浓度较高，而E2和T浓度较低（P <0.05）。高AFC组第8天排卵卵泡和IVG培养基中E2浓度和E2 / P4比值较高（P <0.05）。高AFC组血浆和IVG介质中的AMH浓度较高（P <0.01）。结论颗粒细胞对FSH的反应较弱，导致低AFC组的E2生成量低，导致FSH浓度高和中间卵泡的持续发育。相反，较高的E2浓度会抑制高AFC组的FSH分泌。在整个IVG培养中，高AFC组中的颗粒细胞比低AFC组中的细胞具有产生更多AMH的能力。结论颗粒细胞对FSH的反应较弱，导致低AFC组的E2生成量低，导致FSH浓度高和中间卵泡的持续发育。相反，较高的E2浓度会抑制高AFC组的FSH分泌。在整个IVG培养中，高AFC组中的颗粒细胞比低AFC组中的细胞具有产生更多AMH的能力。结论颗粒细胞对FSH的反应较弱，导致低AFC组的E2生成量低，导致FSH浓度高和中间卵泡的持续发育。相反，较高的E2浓度会抑制高AFC组的FSH分泌。在整个IVG培养中，高AFC组中的颗粒细胞比低AFC组中的细胞具有产生更多AMH的能力。