Shin B C, Fujikura K, Suzuki T, Tanaka S, Takata K
Department of Cell Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan.
Endocrinology. 1997 Sep;138(9):3997-4004. doi: 10.1210/endo.138.9.5369.
Glucose transfer across the placental barrier is crucial for fetal development. To investigate the role of glucose transporter isoforms in the transplacental transfer of glucose, we investigated the localization of glucose transporters GLUT1 and GLUT3 immunohistochemically in the rat placenta. In the labyrinth, the site of maternofetal exchange of substances, both GLUT1 and GLUT3 were present, whereas only GLUT1 was detected in the junctional region. In the labyrinthine wall, which lies between maternal and fetal circulations, GLUT3 exhibited polarized localization; i.e. it was present at the plasma membranes of the maternal blood side in the syncytiotrophoblast layers. GLUT1 was concentrated at plasma membranes of the maternal and fetal blood sides of syncytiotrophoblast layers. The asymmetric distribution of GLUT3 across the placental barrier may suggest asymmetric transfer of glucose, which would be beneficial to provide a stable milieu for fetal development.
葡萄糖跨胎盘屏障的转运对胎儿发育至关重要。为了研究葡萄糖转运蛋白异构体在葡萄糖跨胎盘转运中的作用，我们采用免疫组织化学方法研究了葡萄糖转运蛋白GLUT1和GLUT3在大鼠胎盘中的定位。在物质进行母胎交换的部位——迷路中，GLUT1和GLUT3均有表达，而在连接区仅检测到GLUT1。在位于母体和胎儿循环之间的迷路壁中，GLUT3呈现极化定位，即在合体滋养层母体血侧的质膜上表达。GLUT1则集中在合体滋养层母体和胎儿血侧的质膜上。GLUT3在胎盘屏障中的不对称分布可能提示葡萄糖的不对称转运，这将有利于为胎儿发育提供稳定的环境。
