Two experiments were conducted to determine whether mifepristone (RU486) and PGF₂α activate the phosphatidylinositol hydrolysis pathway during the midluteal phase of the ovine estrous cycle. In experiment 1, ewes on day 8 of the cycle were given 10 μg RU486 or vehicle into the ovarian artery with removal of the corpus luteum (CL) after 10 min. Blood collected prior to and after treatment was analyzed for progesterone. Aliquots of CL were incubated with 10 μCi of ³H-inositol and in the presence and absence of PGF₂α (10 nM) for 15 min. Exposure of CL to RU486 and PGF₂α increased phosphatidylinositol hydrolysis (p < 0.05). Serum progesterone was reduced in both control and RU486-treated ewes (p < 0.05) compared to concentrations before treatments. In experiment 2, aliquots of CL collected from ewes on day 8 of the cycle were incubated with ³H-inositol and exposed to RU486 (2 μM) in the presence and absence of PGF₂α (1 μM) for 15 min. Treatments stimulated phosphatidylinositol hydrolysis as in Exp 1 (p < 0.05). Progesterone concentrations in incubation medium were increased in response to RU486 and PGF₂α (p < 0.05). Collectively, these data suggest that RU486 and PGF₂α act to stimulate phosphatidylinositol hydrolysis in the mature ovine CL.

进行了两个实验以确定米非司酮 (RU486) 和 PGF ₂ α是否在绵羊发情周期的黄体中期激活磷脂酰肌醇水解途径。在实验 1 中，在周期的第 8 天给母羊注入 10 μg RU486 或载体进入卵巢动脉，10 分钟后去除黄体 (CL)。分析治疗前后收集的血液中的孕酮。将等分试样的 CL 与 10 μCi 的³ H-肌醇以及存在和不存在 PGF ₂ α (10 nM)孵育15 分钟。CL 暴露于 RU486 和 PGF ₂α 增加磷脂酰肌醇水解（p < 0.05）。与处理前的浓度相比，对照和 RU486 处理的母羊的血清黄体酮均降低 (p < 0.05)。在实验2中，CL的等分试样从循环与孵育的第8天收集母羊³ H-肌醇和在存在和不存在的PGF暴露于RU486（2μM）₂ 15分钟α（1μM）。处理刺激了磷脂酰肌醇水解，如实验 1 (p < 0.05)。培养培养基中的孕酮浓度随着 RU486 和 PGF ₂ α 的增加而增加（p < 0.05）。总的来说，这些数据表明 RU486 和 PGF ₂ α 用于刺激成熟绵羊CL中的磷脂酰肌醇水解。