Lebrun P, Vanbellinghen A M, Robyn C, Meuris S
Laboratory of Pharmacology, Free University of Brussels, School of Medicine, Belgium.
Cell Calcium. 1995 May;17(5):384-92. doi: 10.1016/0143-4160(95)90112-4.
Kinetics of 45Ca outflow and human placental lactogen (hPL) release were characterized in human placental explants. Measurements of the rate of 45Ca and [3H]-sucrose (extracellular space marker) outflow from preloaded explants showed that, after a 40 min washout period, the 45Ca effluent radioactivity presumably originated from an intracellular compartment. This view was further supported by the La3+ and temperature sensitivity of the 45Ca outflow. Moreover, the addition of ionomycin as well as an increase in the extracellular Ca2+ or Ba2+ concentration provoked a dose-dependent rise in both the 45Ca outflow and hPL release. There were no systematic temporal analogies between the pattern of 45Ca outflow and hPL release. Taken together, these observations suggest that the stimulation of 45Ca outflow reflects an increased rate of 40Ca entry. The present data also extend previous observations indicating that hPL release can be stimulated by Ca2+ entry. Lastly, the 'in vitro' method described herein allows one to compare rapid changes in hPL release with associated ionic events and can be used to further document the relationships between placental secretory responses and cell calcium metabolism.
对人胎盘外植体中45Ca流出动力学和人胎盘催乳素（hPL）释放进行了表征。对预加载外植体中45Ca和[3H] - 蔗糖（细胞外空间标记物）流出速率的测量表明，在40分钟的洗脱期后，45Ca流出放射性可能源自细胞内区室。La3 +和45Ca流出的温度敏感性进一步支持了这一观点。此外，添加离子霉素以及细胞外Ca2 +或Ba2 +浓度的增加会引起45Ca流出和hPL释放的剂量依赖性升高。45Ca流出模式与hPL释放之间没有系统的时间类比关系。综上所述，这些观察结果表明，45Ca流出的刺激反映了40Ca进入速率的增加。目前的数据还扩展了先前的观察结果，表明Ca2 +进入可以刺激hPL释放。最后，本文所述的“体外”方法允许人们将hPL释放的快速变化与相关的离子事件进行比较，并可用于进一步记录胎盘分泌反应与细胞钙代谢之间的关系。
