Permeability of fetal membranes to calcium and magnesium: possible role in preterm labour
Permeability of fetal membranes to calcium and magnesium: possible role in preterm labour
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DOI：
10.1093/humrep/15.9.2018
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发表时间：
2000-09-01
影响因子：
6.1
通讯作者：
Batra, S
中科院分区：
文献类型：
--
作者：
Lemancewicz, A;Laudanska, H;Batra, S
钙（Ca 2+）和镁（Mg 2+）是多种酶的合成活性和分泌过程中的辅因子。这两种阳离子与胎膜的结合和通过膜的扩散都可能是海兰素的合成和/或作用以及一氧化氮（NO）的产生的重要因素，据信海兰素调节子宫肌层活性，特别是用于引产。在本研究中，从经历了足月或早产的妇女获得的绒毛膜羊膜的Ca 2+和Mg 2+的渗透性进行了检查。Ca ~（2+）和Mg ~（2+）的扩散是使用由安装的胎膜分隔的树脂玻璃室系统测量的。使用非线性回归分析计算Mg 2+和Ca 2+通过胎膜的渗透性。数据显示，早产和足月分娩之间的Ca 2+和Mg 2+跨胎膜的扩散存在非常显著的差异。Ca ~（2+）转运系数K在足月和早产分别为0.203h（-1）和0.0223h（-1）。Mg ~（2+）的相应值分别为-0.017 h（-1）和0.051 h（-1）。有人提出，子宫肌层和胎盘中的Ca 2+的大量减少将导致一氧化氮合酶（NOS）活性的下调，从而减少NO的产生。这与由Mg 2+的可用性降低引起的对细胞内Ca 2+转运的影响一起将导致早产中子宫肌层活性增加。
Calcium (Ca2+) and magnesium (Mg2+) are co-factors in the synthetic activity of a variety of enzymes and in the secretory process. Both the binding to fetal membranes and the diffusion through the membranes of these two cations could be important factors in the synthesis and/or action of prostaglandins and generation of nitric oxide (NO) which are believed to regulate myometrial activity particularly for the induction of labour. In the present study, the permeability to Ca2+ and Mg2+ of chorioamniotic membranes obtained from women who had undergone term or preterm labour was examined. Diffusion of Ca2+ and Mg2+ were measured using a system of Plexiglas chambers separated by the mounted fetal membrane. Permeability of Mg2+ and Ca2+ through fetal membranes was calculated using non-linear regression analysis. The data show highly significant differences in the diffusion of Ca2+ and Mg2+ across fetal membranes between preterm and term labour. Transport coefficient K for Ca2+ was 0.203 h(-1) and 0.0223 h(-1) in term and preterm labour respectively. The corresponding values for Mg2+ were -0.017 h(-1) and 0.051 h(-1) respectively. It is proposed that a considerable reduction in Ca2+ available to myometrium and placenta would result in down-regulation of nitric oxide synthase (NOS) activity and thereby a reduction in NO production. This together with an effect on intracellular Ca2+ transport resulting from a reduced availability of Mg2+ would lead to increased myometrial activity in preterm labour.