Wu W X, Ma X H, Nathanielsz P W
Laboratory for Pregnancy and Newborn Research, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853-6401, USA.
Am J Obstet Gynecol. 1999 Mar;180(3 Pt 1):744-9. doi: 10.1016/s0002-9378(99)70282-6.
Our purpose was to investigate, first, whether there were changes in the abundance of prostacyclin synthase protein in intrauterine tissues of pregnant ewes in association with spontaneous term labor. Second, we examined the effect of either estradiol or progesterone, or both, on regulation of prostacyclin synthase protein abundance in uterine tissues using an ovariectomized nonpregnant sheep model.
The abundance of prostacyclin synthase protein was quantified by Western blot analysis in the myometrium, endometrium, and placenta of pregnant ewes in spontaneous term labor (n = 6) and term control ewes not in labor (n = 6). The changes of prostacyclin synthase in the myometrium and endometrium of 20 ovariectomized nonpregnant sheep (n = 5 for each group) were evaluated after treatment with estradiol, progesterone, or both.
Prostacyclin synthase protein was present in pregnant and nonpregnant sheep myometrium, endometrium, and placenta at a molecular weight of about 55 kd. At spontaneous term labor the level of prostacyclin synthase decreased in endometrium (P <.05), increased in myometrium (P <.05), and remained unchanged in placenta. Estradiol and progesterone had no effect on prostacyclin synthase protein abundance in nonpregnant ovine endometrium and myometrium.
The decrease in prostacyclin synthase in pregnant sheep endometrium during labor may indicate paracrine interactions between the endometrium, the myometrium, fetal membranes, or a combination of these. The significant increase of prostacyclin synthase in pregnant sheep myometrium at spontaneous term labor may contribute to the increased uterine sensitivity to oxytocin or stimulate vasodilatation during labor to increase myometrial blood flow. Neither estradiol nor progesterone at the dosages studied changed prostacyclin synthase expression in the nonpregnant myometrium and endometrium. The molecular mechanism or mechanisms that differentially regulate prostacyclin synthase expression in pregnant uterine tissues merit further study.
我们的目的首先是研究妊娠母羊子宫内组织中前列环素合酶蛋白丰度与足月自然分娩是否有关。其次，我们使用去卵巢未孕绵羊模型，研究雌二醇或孕酮或两者对子宫组织中前列环素合酶蛋白丰度调节的影响。
通过蛋白质印迹分析对足月自然分娩的妊娠母羊（n = 6）和未分娩的足月对照母羊（n = 6）的子宫肌层、子宫内膜和胎盘组织中前列环素合酶蛋白的丰度进行定量。对20只去卵巢未孕绵羊（每组n = 5），在给予雌二醇、孕酮或两者后，评估子宫肌层和子宫内膜中前列环素合酶的变化。
前列环素合酶蛋白存在于妊娠和未孕绵羊的子宫肌层、子宫内膜和胎盘中，分子量约为55kd。在足月自然分娩时，子宫内膜中前列环素合酶水平降低（P <.05），子宫肌层中升高（P <.05），胎盘组织中无变化。雌二醇和孕酮对未孕绵羊子宫内膜和子宫肌层中前列环素合酶蛋白丰度无影响。
分娩期间妊娠绵羊子宫内膜中前列环素合酶减少可能表明子宫内膜、子宫肌层、胎膜之间或这些组织联合存在旁分泌相互作用。足月自然分娩时妊娠绵羊子宫肌层中前列环素合酶显著增加可能有助于子宫对催产素敏感性增加或在分娩期间刺激血管舒张以增加子宫肌层血流。在所研究的剂量下，雌二醇和孕酮均未改变未孕子宫肌层和子宫内膜中前列环素合酶的表达。在妊娠子宫组织中差异调节前列环素合酶表达的分子机制值得进一步研究。
