Robinson R S, Mann G E, Lamming G E, Wathes D C
Reproduction and Development Group, Royal Veterinary College, Hawkshead Road, Potters Bar, Hertfordshire EN6 1NB, UK.
Reproduction. 2001 Dec;122(6):965-79.
This study examined the expression patterns of oxytocin and steroid receptors in the bovine endometrium during the oestrous cycle and early pregnancy to elucidate their respective roles in the regulation of luteolysis and the maternal recognition of pregnancy. In Expt 1, uterine biopsies were collected from four cows throughout three oestrous cycles each, to provide daily samples. In Expt 2, uterine tissue was collected on days 12, 14, 16 and 18 of the oestrous cycle (n = 20) or early pregnancy (n = 16). Oxytocin receptor, oestrogen receptor alpha and progesterone receptor mRNAs were localized by in situ hybridization, and localization of oestrogen receptor and progesterone receptor was confirmed by immunocytochemistry. All three receptors showed time- and cell-specific expression patterns. Oestrogen receptor alpha increased in all regions at oestrus but high concentrations were also found in the luminal epithelium during the mid-luteal phase and in the deep glands throughout the oestrous cycle. Progesterone receptor expression was higher in the stroma than it was in the types of epithelial cell, and increased expression was observed at oestrus and during the early luteal phase. The cyclical upregulation of oxytocin receptors in the luminal epithelium on about day 16 was not related to preceding changes in the endometrial expression of either oestradiol alpha or progesterone receptors. During early pregnancy, oxytocin receptor expression was suppressed. Oestrogen receptor a concentrations increased in the non-pregnant cows and decreased in the pregnant cows between days 16 and 18, but these changes followed rather than preceded the upregulation of oxytocin receptors in the non-pregnant cows. It is concluded that the initial upregulation of oxytocin receptors in the luminal epithelium, which triggers luteolysis, is not associated directly with changes in expression of oestrogen receptor alpha.
本研究检测了发情周期和妊娠早期牛子宫内膜中催产素和类固醇受体的表达模式，以阐明它们在黄体溶解调节和母体妊娠识别中的各自作用。在实验1中，从4头奶牛的三个发情周期中每天采集子宫活检组织样本。在实验2中，在发情周期（n = 20）或妊娠早期（n = 16）的第12、14、16和18天采集子宫组织。通过原位杂交定位催产素受体、雌激素受体α和孕激素受体mRNA，并通过免疫细胞化学确认雌激素受体和孕激素受体的定位。所有三种受体均表现出时间和细胞特异性表达模式。雌激素受体α在发情期所有区域均增加，但在黄体中期的腔上皮以及整个发情周期的深部腺体中也发现高浓度表达。孕激素受体在基质中的表达高于上皮细胞类型，且在发情期和黄体早期观察到表达增加。大约在第16天腔上皮中催产素受体的周期性上调与子宫内膜中雌二醇α或孕激素受体表达的先前变化无关。在妊娠早期，催产素受体表达受到抑制。在第16至18天之间，未怀孕奶牛的雌激素受体a浓度增加，而怀孕奶牛的雌激素受体a浓度降低，但这些变化是在未怀孕奶牛中催产素受体上调之后而非之前出现的。得出的结论是，引发黄体溶解的腔上皮中催产素受体的初始上调与雌激素受体α表达的变化没有直接关联。
