Meyer H H, Mittermeier T, Schams D
Institut für Physiologie der Südd. Versuchs- und Forschungsanstalt für Milchwirtschaft, Technische Universität München, Freising-Weihenstephan, FRG.
Acta Endocrinol (Copenh). 1988 May;118(1):96-104. doi: 10.1530/acta.0.1180096.
The levels of oxytocin receptor (OTR), cytosolic progestin receptor (cPR), cytosolic and nuclear estrogen receptor (cER, nER) were measured in the endometrium of 28 heifers that had been slaughtered on a defined day of the estrous cycle. In an additional, trial endometrial tissue obtained from 78 heifers or cows at the abattoir was analysed for OTR. OTR was absent during the luteal phase (after day 6), but a minor elevation was observed after day 15. OTR increased rapidly after luteolysis on days 17-18 reaching a maximum during estrous on day 21, and decreased again during days 1-6. cER and cPR were different to OTR but followed a similar pattern with maximal levels during days 1-8 of the estrous cycle. At day 12 both receptors were minimal and increased again towards day 21. nER was maximal at day 19-21 coinciding with maximal estradiol levels and estrous. Our data indicate that owing to an increasing sensitivity of the endometrium to progesterone and estradiol after day 12, these steroids may be mainly responsible for the initiation of first PGF2 alpha surges and luteolysis. Oxytocin seems to be of minor importance at this stage owing to low sensitivity of the endometrium for oxytocin.
在发情周期特定日期屠宰的28头小母牛的子宫内膜中，检测了催产素受体（OTR）、胞质孕激素受体（cPR）、胞质和核雌激素受体（cER、nER）的水平。另外，对从屠宰场的78头小母牛或母牛获得的子宫内膜组织进行了OTR分析。OTR在黄体期（第6天后）不存在，但在第15天后观察到轻微升高。在第17 - 18天黄体溶解后，OTR迅速增加，在第21天发情期达到最大值，然后在第1 - 6天再次下降。cER和cPR与OTR不同，但遵循相似模式，在发情周期的第1 - 8天达到最高水平。在第12天，两种受体均降至最低，并在接近第21天时再次升高。nER在第19 - 21天达到最大值，与雌二醇水平和发情的最大值一致。我们的数据表明，由于第12天后子宫内膜对孕酮和雌二醇的敏感性增加，这些类固醇可能是首次PGF2α激增和黄体溶解开始的主要原因。由于子宫内膜对催产素的敏感性较低，催产素在这个阶段似乎不太重要。
