Lamming G E, Wathes D C, Flint A P, Payne J H, Stevenson K R, Vallet J L
Department of Animal Physiology and Environmental Science, University of Nottingham, Sutton Bonington, Loughborough, Leics, UK.
J Reprod Fertil. 1995 Sep;105(1):165-75. doi: 10.1530/jrf.0.1050165.
Luteolysis in sheep is associated with uterine secretion of pulses of prostaglandin F2 alpha (PGF2 alpha) due to the action of luteal oxytocin on endometrial oxytocin receptors. For pregnancy to become established inhibition of oxytocin receptors is important as an antiluteolytic mechanism. The maternal recognition of pregnancy in cattle and sheep involves production, by the trophoblast, of a type 1 interferon (IFN-tau) that suppresses uterine development of oxytocin receptors and the generation of luteolytic episodes of PGF2 alpha. The action of IFN-tau in surgically prepared unilaterally pregnant ewes was investigated. Finn-Dorset ewes were anaesthetized on day 6 or 7 of the oestrous cycle and one uterine horn was surgically isolated at the uterine bifurcation from the body of the uterus. Ewes were mated at the subsequent oestrus either by a fertile or by a vasectomized ram and killed on day 13 or 16 after mating. On day 16, in the non-pregnant ewes, there was no measurable uterine IFN-tau but there were high concentrations of oxytocin receptors in both horns. In the pregnant ewes on day 16 after mating, the oxytocin receptor concentration was 45 +/- 11 fmol mg-1 protein in the pregnant horn and 585 +/- 131 fmol mg-1 in the non-pregnant horn. Antiviral activity was 5.8 x 10(7) +/- 5.2 x 10(7) U ml-1 in the pregnant horn and 2.9 x 10(3) +/- 1.2 x 10(3) U ml-1 in the non-pregnant horn. Thus, 16 days after mating, the pregnant horn exhibited high antiviral activity but oxytocin receptors were suppressed, while in the same endocrine environment (characteristic of pregnancy) there were low IFN-tau and high oxytocin receptor concentrations in the isolated horn equivalent to those expected at the onset of luteolysis. In situ hybridization to ovine mRNA encoding the oxytocin receptor and autoradiographic studies using the 125I-labelled oxytocin antagonist d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]-vasotocin both showed that the large amount of oxytocin receptor message and binding sites in the endometrium of the isolated horn were localized in the luminal epithelium. Immunocytochemical studies showed that there was a suppression of oestradiol receptors in the pregnant horn but high concentrations equivalent to those at oestrus were present in the isolated horn. The content of progesterone receptors was low in the stromal tissue only in both horns, a pattern of localization similar to that seen in the late luteal phase and in early pregnancy.(ABSTRACT TRUNCATED AT 400 WORDS)
绵羊的黄体溶解与由于黄体分泌的催产素作用于子宫内膜催产素受体，导致子宫分泌脉冲式前列腺素F2α（PGF2α）有关。对于妊娠的确立，抑制催产素受体作为一种抗黄体溶解机制很重要。牛和绵羊母体对妊娠的识别涉及滋养层产生1型干扰素（IFN-tau），其抑制子宫催产素受体的发育以及PGF2α黄体溶解发作的产生。研究了IFN-tau在手术制备的单侧妊娠母羊中的作用。芬多塞特母羊在发情周期的第6天或第7天麻醉，一个子宫角在子宫分叉处从子宫体分离出来。母羊在随后的发情期与可育或输精管切除的公羊交配，并在交配后第13天或第16天处死。在第16天，未怀孕的母羊子宫中没有可测量的IFN-tau，但两个子宫角中都有高浓度的催产素受体。交配后第16天的怀孕母羊中，怀孕子宫角的催产素受体浓度为45±11 fmol mg-1蛋白，未怀孕子宫角为585±131 fmol mg-1。抗病毒活性在怀孕子宫角为5.8×10(7)±5.2×10(7) U ml-1，未怀孕子宫角为2.9×10(3)±1.2×10(3) U ml-1。因此，交配后16天，怀孕子宫角表现出高抗病毒活性，但催产素受体受到抑制，而在相同的内分泌环境（妊娠特征）下，分离子宫角中的IFN-tau浓度低，催产素受体浓度高，与黄体溶解开始时预期的浓度相当。对编码催产素受体的绵羊mRNA进行原位杂交以及使用125I标记的催产素拮抗剂d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]-加压素进行放射自显影研究均表明，分离子宫角子宫内膜中大量的催产素受体信息和结合位点位于腔上皮。免疫细胞化学研究表明，怀孕子宫角中雌二醇受体受到抑制，但分离子宫角中存在与发情期相当的高浓度。仅在两个子宫角的基质组织中孕酮受体含量低，这种定位模式与黄体后期和妊娠早期所见相似。（摘要截断于400字）
