Wollenhaupt K, Kettler A, Brüssow K P, Schneider F, Kanitz W, Einspanier R
Unit of Reproductive Biology, Research Institute for the Biology of Farm Animals, Dummerstorf, Germany.
Reprod Fertil Dev. 2001;13(2-3):167-76. doi: 10.1071/rd01017.
Growth factors, such as epidermal growth factor (EGF), have been suggested to mediate local effects of steroid hormones within female reproductive tissue. In the present study, the influence of estrogen on the expression and bioactivity of the EGF receptor (EGF-R) system was investigated in pigs. Oviducal and endometrial tissue from gilts was analysed either at two different time points after ovulation (Day 12 and Day 20), or from ovariectomized animals, with or without steroid-replacement treatment. Estrogen receptor protein concentrations were significantly down-regulated both in oviducal and endometrial tissue under estrogen-influence, in contrast to increased progesterone receptor concentrations. Transcript levels of EGF and transforming growth factor alpha remained unchanged in both the oviduct and endometrium during treatment. Oviducal EGF-R mRNA was found to be increased after estradiol treatment with concurrent increases in EGF-R protein. However, in endometrial tissue of estradiol-substituted ovariectomized pigs, the receptor transcript was significantly reduced, indicating a different regulation of EGF-R transcription within the endometrium. The bioactivity of the EGF-R, analysed by tyrosine kinase assays, was preserved throughout experiments in the porcine oviduct and endometrium without obvious changes caused by the steroids. In conclusion, estradiol may play a key role during the proliferation and differentiation of porcine oviducal tissue by activating the important paracrine or autocrine EGF system through its receptor. The cell-specific influence of progesterone during regulation of the EGF-R expression in the endometrium requires further investigation.
生长因子，如表皮生长因子（EGF），被认为可介导类固醇激素在雌性生殖组织中的局部作用。在本研究中，研究了雌激素对猪EGF受体（EGF-R）系统表达和生物活性的影响。对后备母猪的输卵管和子宫内膜组织，在排卵后的两个不同时间点（第12天和第20天）进行分析，或对去卵巢动物进行分析，这些动物接受或未接受类固醇替代治疗。在雌激素影响下，输卵管和子宫内膜组织中的雌激素受体蛋白浓度均显著下调，相反，孕激素受体浓度升高。治疗期间，输卵管和子宫内膜中EGF和转化生长因子α的转录水平均保持不变。发现雌二醇处理后输卵管EGF-R mRNA增加，同时EGF-R蛋白也增加。然而，在雌二醇替代的去卵巢猪的子宫内膜组织中，受体转录物显著减少，表明子宫内膜中EGF-R转录的调控不同。通过酪氨酸激酶测定分析的EGF-R生物活性在整个实验过程中在猪输卵管和子宫内膜中得以保留，未因类固醇而产生明显变化。总之，雌二醇可能通过其受体激活重要的旁分泌或自分泌EGF系统，在猪输卵管组织的增殖和分化过程中发挥关键作用。孕激素在子宫内膜中对EGF-R表达调控的细胞特异性影响需要进一步研究。
