Ramirez RJ, Gibson M, Kalenic J, Einzig S, Omar HA
Department of Physiology, West Virginia University School of Medicine, Morgantown, West Virginia
J Matern Fetal Investig. 1998 Jun;8(2):61-5.
Background: We have recently reported that progesterone caused a receptor-mediated, cAMP-dependent relaxation in isolated placental arteries and veins from normal term pregnancies that may be important in maintaining adequate blood flow in the placental circulation. Objective: To further investigate the activity of progesterone and some of its metabolites in both placental and umbilical vessels. Study design: Isolated human placental and umbilical arteries and veins from normal term pregnancies, incubated in Krebs-bicarbonate buffer and submaximally precontracted with potassium chloride, were exposed to cumulative concentrations (0.01-30 µm) of progesterone, 5beta-pregnane-3,20-dione, 5alpha-pregnane-3,20-dione, or 5alpha-pregnane-3beta-ol-20-one. Results: All experimental progestins produced concentration-dependent relaxations in precontracted human placental and umbilical arteries and veins. These relaxations were endothelium-independent. Progesterone and 5beta-pregnane-3,20-dione appeared to be the most potent and efficient of the tested progestins, whereas 5alpha-pregnane-3beta-ol-20-one produced the least relaxation in the same vessels. Conclusions: These results suggest that not only progesterone, but also its metabolites, may be of physiological importance in the regulation of umbilico-placental vascular tone. Additionally, it appears that the umbilical blood vessels possess the same relaxation to progesterone as placental arteries and veins. Taken together, these results indicate a potential role for progesterone and its metabolites in maintaining adequate blood flow in the umbilico-placental circulation.
我们最近报道，孕酮可引起足月妊娠分离出的胎盘动脉和静脉中受体介导的、环磷酸腺苷（cAMP）依赖性舒张，这可能对维持胎盘循环中充足的血流很重要。目的：进一步研究孕酮及其一些代谢产物在胎盘和脐血管中的活性。研究设计：将来自足月妊娠的人胎盘和脐动脉及静脉分离出来，置于 Krebs - 碳酸氢盐缓冲液中，并用氯化钾进行亚最大预收缩，然后暴露于孕酮、5β - 孕烷 - 3,20 - 二酮、5α - 孕烷 - 3,20 - 二酮或 5α - 孕烷 - 3β - 醇 - 20 - 酮的累积浓度（0.01 - 30 µm）下。结果：所有实验性孕激素均在预收缩的人胎盘和脐动脉及静脉中产生浓度依赖性舒张。这些舒张与内皮无关。孕酮和 5β - 孕烷 - 3,20 - 二酮似乎是测试孕激素中最有效力和效率的，而 5α - 孕烷 - 3β - 醇 - 20 - 酮在相同血管中产生的舒张最少。结论：这些结果表明，不仅孕酮，而且其代谢产物在调节脐 - 胎盘血管张力方面可能具有生理重要性。此外，脐血管似乎对孕酮的舒张反应与胎盘动脉和静脉相同。综上所述，这些结果表明孕酮及其代谢产物在维持脐 - 胎盘循环中充足的血流方面具有潜在作用。
