Wise M E, Glass J D, Nett T M
J Anim Sci. 1986 Apr;62(4):1021-8. doi: 10.2527/jas1986.6241021x.
The sensitivity of the hypothalamic-pituitary axis to estradiol was evaluated by monitoring changes in the concentration of receptors for estradiol during gestation and the postpartum period of the ewe. Ewes that had been bred during anestrus so that lambing would occur during the breeding season were killed on d 50 and 140 of gestation or on d 2, 13, 22 and 35 postpartum. Total cytosolic receptors for estradiol were quantified in the anterior and posterior hypothalamus, median eminence, anterior pituitary and cerebral cortex. Concentration and total number of receptors for estradiol in the anterior and posterior hypothalamus and anterior pituitary gland during gestation through d 13 postpartum were similar but increased (P less than .05) by d 22 and 35 postpartum. Changes in the concentration of receptors for estradiol were tissue-specific because stage of reproduction did not influence the number of receptors for estradiol in the median eminence or cerebral cortex. Increases in the concentration of receptors for estradiol in hypothalamic and pituitary tissues on d 22 postpartum immediately preceded the onset of normal ovarian cyclicity in ewes. From these data we conclude that resumption of reproductive cycles in postpartum ewes occurs about the time concentrations of receptors for estradiol in the anterior pituitary gland and hypothalamus increase.
通过监测母羊妊娠期和产后雌二醇受体浓度的变化，评估下丘脑 - 垂体轴对雌二醇的敏感性。在发情间期配种以便在繁殖季节产羔的母羊，于妊娠第50天和140天或产后第2天、13天、22天和35天宰杀。对下丘脑前部和后部、正中隆起、垂体前叶和大脑皮质中的雌二醇总胞质受体进行定量分析。妊娠至产后第13天期间，下丘脑前部和后部以及垂体前叶中雌二醇受体的浓度和总数相似，但产后第22天和35天时增加（P小于0.05）。雌二醇受体浓度的变化具有组织特异性，因为生殖阶段不影响正中隆起或大脑皮质中雌二醇受体的数量。产后第22天，下丘脑和垂体组织中雌二醇受体浓度的增加紧接着母羊正常卵巢周期的开始。从这些数据我们得出结论，产后母羊生殖周期的恢复大约发生在垂体前叶和下丘脑雌二醇受体浓度增加的时候。
