Burgess K M, Jenkin G, Ralph M M, Thorburn G D
Department of Physiology, Monash University, Clayton, Victoria, Australia.
J Endocrinol. 1992 Sep;134(3):353-60. doi: 10.1677/joe.0.1340353.
The effect of RU486, a synthetic progesterone receptor antagonist, on basal uterine prostaglandin (PG) release and release in response to oxytocin injection has been investigated in late-pregnant sheep (days 135-140 of gestation). Fifteen hours after i.m. injection of RU486 (50 mg; n = 5) or vehicle alone (n = 4), bolus injections of oxytocin (50, 500 and 5000 mU) were administered via a uterine artery ipsilateral to the pregnant uterine horn at 2-hourly intervals. Utero-ovarian vein concentrations of 13,14-dihydro-15-keto PGF2 alpha (PGFM) and PGE2 were determined before and during oxytocin stimulation. Basal concentrations of both PGFM and PGE2 were significantly (P < 0.001) increased in ewes 15 h after RU486 administration compared with ewes receiving vehicle alone. Concentrations of PGFM, but not PGE2, increased significantly (P < 0.001) following injection of each dose of oxytocin in both treated and untreated animals. The response to oxytocin, measured both as the area under the curve and as the peak height of PGFM release, was significantly (P < 0.05) greater in RU486-treated ewes. There was no significant effect of oxytocin on the area or peak height of PGE2 response in either RU486-treated or control animals. These results demonstrate that treatment of late-pregnant ewes with RU486 results in an increase in basal uterine PGFM and PGE2 as well as oxytocin-stimulated PGFM release.
在妊娠后期的绵羊（妊娠135 - 140天）中，研究了合成孕激素受体拮抗剂RU486对子宫基础前列腺素（PG）释放以及对催产素注射反应释放的影响。肌肉注射RU486（50毫克；n = 5）或单独注射溶媒（n = 4）15小时后，每隔2小时通过与妊娠子宫角同侧的子宫动脉进行催产素（50、500和5000毫单位）推注。在催产素刺激前和刺激期间测定子宫卵巢静脉中13,14 - 二氢 - 15 - 酮PGF2α（PGFM）和PGE2的浓度。与单独接受溶媒的母羊相比，给予RU486后15小时的母羊PGFM和PGE2的基础浓度均显著升高（P < 0.001）。在接受治疗和未接受治疗的动物中，每次注射催产素后，PGFM的浓度均显著升高（P < 0.001），但PGE2的浓度未显著升高。以曲线下面积和PGFM释放的峰值高度衡量，RU486治疗的母羊对催产素的反应显著更大（P < 0.05）。在RU486治疗的动物或对照动物中，催产素对PGE2反应的面积或峰值高度均无显著影响。这些结果表明，用RU486治疗妊娠后期的母羊会导致子宫基础PGFM和PGE2增加，以及催产素刺激的PGFM释放增加。
