Albrecht E D, Crenshaw M C, Pepe G J
Department of Obstetrics and Gynecology, University of Maryland School of Medicine, Baltimore 21201.
Am J Obstet Gynecol. 1989 Jan;160(1):237-41. doi: 10.1016/0002-9378(89)90128-2.
In baboons, the placenta remains in situ and functional with respect to the potential for aromatization after removal of the fetus (fetectomy). Fetectomy therefore was used to study effects of the fetus and estrogen on placental delivery. By term, serum estradiol levels in untreated, intact baboons had increased to 4 to 8 ng/ml, and fetoplacental delivery occurred on day 184 +/- 1 (mean +/- SE). Fetectomy at midgestation resulted in a nondetectable serum estradiol level and a marked decline in progesterone level; however, placentas were maintained in situ and were delivered on day 171 +/- 6. After fetectomy therefore the initiation of placental delivery and, presumably, myometrial contractility did not require an elevation in estrogen. Administration of estradiol (1 to 10 mg/day) to baboons after fetectomy resulted in normal serum estradiol concentrations, but placental delivery was prevented. When estrogen was discontinued on days 215 to 250, the serum estradiol level declined, and placental delivery occurred on day 262 +/- 18, a value greater than in intact baboons or untreated baboons after fetectomy (p less than 0.001). Thus estrogen prevented placental delivery in baboons after fetectomy.
在狒狒中，去除胎儿（胎儿切除术）后，胎盘仍留在原位且具有芳香化的功能潜力。因此，胎儿切除术被用于研究胎儿和雌激素对胎盘娩出的影响。足月时，未处理的完整狒狒血清雌二醇水平已升至4至8 ng/ml，胎儿胎盘在184±1天（平均值±标准误）娩出。妊娠中期进行胎儿切除术导致血清雌二醇水平无法检测到，孕酮水平显著下降；然而，胎盘仍留在原位，并在171±6天娩出。因此，胎儿切除术后胎盘娩出的启动以及大概子宫肌层的收缩性并不需要雌激素升高。胎儿切除术后给狒狒注射雌二醇（1至10 mg/天）可导致血清雌二醇浓度正常，但胎盘娩出受到阻止。当在215至250天停用雌激素时，血清雌二醇水平下降，胎盘在262±18天娩出，该值高于完整狒狒或胎儿切除术后未处理的狒狒（p<0.001）。因此，雌激素在胎儿切除术后阻止了狒狒的胎盘娩出。
