Puri C P, Garfield R E
Biol Reprod. 1982 Nov;27(4):967-75. doi: 10.1095/biolreprod27.4.967.
To study the temporal relationship between changes in hormone levels with the development of myometrial gap junctions, rats were sacrificed to collect uterine vein blood and uterine tissues daily from Day 15 to Day 20 of pregnancy, every 3 h on Day 21, during delivery, and 3 h after parturition. Levels of progesterone, estradiol and prostaglandin F2 alpha (PGF2 alpha) were measured by specific radioimmunoassay methods, and myometrial gap junctions were measured by quantitative electron microscopy. Levels of progesterone declined markedly on Day 19 of pregnancy, at least 60 to 70 h before the expected time of parturition and the decrease was more rapid in uterine tissue than in plasma. Levels of estradiol started to increase after Day 19, showed a marked rise on Day 21, and peaked at the time of parturition. Levels of PGF2 alpha also increased rapidly after Day 20, when progesterone levels had already dropped by 67% and 84% of Day 15 levels in plasma and tissue samples, respectively. Gap junctions, identified as 5- or 7-lined structures with a gap of about 2 nm at 100,000X magnification were present in the pregnant uterus. However, their number, size and area were increased significantly on Day 21 and during parturition. Increased numbers of gap junctions were still present in rats killed 3 h after parturition. These studies demonstrate that a decrease in progesterone levels followed by increases in estradiol and PGF2 alpha are coincident with the formation of gap junctions which in turn may coordinate the increased uterine activity required for parturition.
为了研究激素水平变化与子宫肌层缝隙连接发育之间的时间关系，在妊娠第15天至第20天每天处死大鼠以收集子宫静脉血和子宫组织，在第21天每3小时收集一次，分娩期间以及分娩后3小时收集。通过特定的放射免疫分析方法测量孕酮、雌二醇和前列腺素F2α（PGF2α）的水平，并通过定量电子显微镜测量子宫肌层缝隙连接。孕酮水平在妊娠第19天显著下降，至少在预期分娩时间前60至70小时，子宫组织中的下降比血浆中更快。雌二醇水平在第19天后开始升高，在第21天显著上升，并在分娩时达到峰值。PGF2α水平在第20天后也迅速升高，此时血浆和组织样本中孕酮水平分别已降至第15天水平的67%和84%。在妊娠子宫中可识别出缝隙连接，在100,000倍放大倍数下为5或7排结构，间隙约为2纳米。然而，它们的数量、大小和面积在第21天和分娩期间显著增加。分娩后3小时处死的大鼠中仍存在数量增加的缝隙连接。这些研究表明，孕酮水平下降后雌二醇和PGF2α水平升高与缝隙连接的形成同时发生，这反过来可能协调分娩所需的子宫活动增加。
