Kobayashi M, Akahane M, Minami K, Moro M, Ajisawa Y, Inoue Y, Kawarabayashi T
Discovery Research, R&D, Kissei Pharmaceutical Co, Ltd, Nagano, Japan.
Am J Obstet Gynecol. 1999 Mar;180(3 Pt 1):621-7. doi: 10.1016/s0002-9378(99)70264-4.
Our purpose was to compare the functional roles of oxytocin in term and preterm labor in rats by both biochemical and pharmacologic means.
We determined the myometrial oxytocin receptor density and the maternal plasma concentrations of oxytocin and progesterone on gestational days 18, 20, and 22 (morning) and at the onset of delivery (day 22 afternoon) in rats with labor at term and at the onset of delivery (day 20 afternoon) in rats in preterm labor induced by the combined use of bilateral ovariectomy and estradiol injection. We also evaluated the effects of an oxytocin antagonist, L-366,509, on the initiation of both term and preterm labor.
The number of tritiated oxytocin binding sites in myometrial membranes rapidly increased on gestational day 22 (morning) in rats with term labor. Plasma progesterone level decreased in an inverse fashion. A rapid increase in circulating oxytocin concentration was observed at the onset of delivery in rats in labor at term. Both the plasma oxytocin concentration and the receptor density had the same values in rats with preterm labor as in rats with term labor. L-366,509 delayed the initiation of labor in rats with term and preterm labor in a dose-dependent manner.
It is confirmed biochemically and pharmacologically that oxytocin plays an important role in the initiation of both term and preterm labor in rats. The oxytocin antagonist examined was able to delay term and preterm labor, so it might prove useful in clinical practice for the treatment of preterm labor.
我们的目的是通过生化和药理学方法比较催产素在大鼠足月分娩和早产中的功能作用。
我们测定了足月分娩大鼠在妊娠第18、20和22天（上午）以及分娩开始时（第22天下午），以及双侧卵巢切除联合雌二醇注射诱导早产的大鼠在分娩开始时（第20天下午）子宫肌层催产素受体密度以及母体血浆中催产素和孕酮的浓度。我们还评估了催产素拮抗剂L-366,509对足月分娩和早产发动的影响。
足月分娩大鼠子宫肌层膜中氚标记的催产素结合位点数量在妊娠第22天（上午）迅速增加。血浆孕酮水平呈相反下降。足月分娩大鼠在分娩开始时观察到循环催产素浓度迅速升高。早产大鼠的血浆催产素浓度和受体密度与足月分娩大鼠相同。L-366,509以剂量依赖的方式延迟了足月和早产大鼠的分娩发动。
通过生化和药理学方法证实，催产素在大鼠足月分娩和早产发动中起重要作用。所检测的催产素拮抗剂能够延迟足月和早产，因此在临床治疗早产中可能证明是有用的。
