Interactions of circulating estradiol and progesterone on changes in endometrial area and pituitary responsiveness to GnRH
Interactions of circulating estradiol and progesterone on changes in endometrial area and pituitary responsiveness to GnRH
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DOI：
10.1093/biolre/ioaa065
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发表时间：
2020-09-01
影响因子：
3.6
通讯作者：
Sartori, Roberto
中科院分区：
文献类型：
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作者：
Motta, Jessica C. L.;Madureira, Guilherme;Sartori, Roberto
发情期循环孕酮（P4）和雌二醇（E2）的变化引起子宫内膜功能和垂体促性腺激素释放的动态变化。观察P4和E2对子宫内膜和垂体的独立作用和联合作用。在初步研究中，通过去除黄体和卵泡>= 5 mm，在18小时内逐渐去除阴道内P4植入物，并在48小时内增加雌二醇苯甲酯剂量，以高E2 （n = 9）或低E2 （n = 9）模拟早情，建立了外源性激素模型。降低P4，增加E2，并增加高E2奶牛的子宫内膜面积（EA）模拟发情。主试验采用2 × 2因子设计，E2高，P4低（n = 11）；高E2和高P4 (n = 11)；E2低，P4高（n = 11）；E2低，P4低（n = 10）。48 h测定促性腺激素释放激素（GnRH）诱导的促黄体生成素（LH）和促卵泡激素（FSH）释放量。采用统计分析系统procmix对变量进行分析。只有高e2和低p4奶牛的EA在48 h内显著增加。促卵泡刺激素方面，高E2奶牛GnRH后曲线下面积（AUC）和促卵泡刺激素峰值均大于低E2奶牛，高P4的负面影响较轻。高E2组LH的峰值浓度和AUC是低E2组的2倍，低P4组LH的峰值浓度和AUC是高P4组LH的2倍。因此，在发情前期，子宫和垂体的最大变化依赖于低P4和高E2，但E2和P4对不同生理反应的调节不同。子宫内膜的变化依赖于低P4和高E2，而gnrh诱导的FSH分泌主要依赖于高E2， gnrh诱导的LH分泌独立地因高E2而增加或因高P4而减少。
Changes in circulating progesterone (P4) and estradiol (E2) during proestrus produce dynamic changes in endometrial function and pituitary release of gonadotropins. Independent and combined effects of P4 and E2 on endometrium and pituitary were evaluated. In a preliminary study, an exogenous hormone model of proestrus was created by removal of corpus luteum and follicles >= 5 mm followed by gradual removal of intravaginal P4 implants during 18 h and treatment with increasing doses of estradiol benzoate during 48 h to mimic proestrus using high E2 (n = 9) or low E2 (n = 9). Decreased P4, increased E2, and increased endometrial area (EA) simulated proestrus in high-E2 cows and this was used subsequently. The main experiment used a 2 x 2 factorial design with: high E2 and low P4 (n = 11); high E2 and high P4 (n = 11); low E2 and high P4 (n = 11); low E2 and low P4 (n = 10). At 48 h, gonadotropin-releasing hormone (GnRH)-induced luteinizing hormone (LH) and follicle stimulating hormone (FSH) release was determined. Variables were analyzed using PROCMIXED of Statistical Analysis System. The EA increased dramatically during 48 h only in highE2 and low-P4 cows. For FSH, high-E2 cows had greater area under the curve (AUC) and FSH peak after GnRH than low E2, with mild negative effects of high P4. For LH, concentration at peak and AUC were 2-fold greater in high E2 compared to low-E2 groups, with low P4 also 2-fold greater than high-P4 groups. Thus, maximal changes in uterus and pituitary during proestrus depend on both low P4 and high E2, but different physiologic responses are regulated differently by E2 and P4. Changes in endometrium depend on low P4 and high E2, whereas GnRH-induced FSH secretion primarily depends on high E2, and GnRH-induced LH secretion is independently increased by high E2 or reduced by high P4.