Sen A, Ghosh P K, Mukherjea M
Department of Biochemistry, University College of Science, Calcutta, India.
Mol Cell Biochem. 1998 Oct;187(1-2):183-90. doi: 10.1023/a:1006839711587.
Human placental syncytiotrophoblast basal membrane plays an important role in transfer of nutrients from the mother to the growing fetus all throughout gestation. The membrane lipid composition together with the bilayer fluidity is found to be the major index in modulation of these transport processes. In the present study, the effects of changing lipid composition on the placental basal membrane fluidity and the modulating influence of the latter on membrane enzyme and transport functions with progress of gestation,were investigated. Steady-state fluorescence analysis using 1,6-diphenyl- 1,3,5 hexatriene as the probe, indicated a decrease in fluorescence anisotropy of both labeled native membrane vesicles and liposomes prepared from lipids extracted from the basal membrane vesicles, signifying increased bilayer fluidity with progress of gestation. This in turn, was successfully correlated to the lowering of cholesterol content and enhanced phospholipid concentration with a steady decrease in cholesterol/phospholipid ratio during placental development. Enhanced Na+-K+-ATPase activity and steady-state glucose uptake across basal membrane with gestational progress suggested modulation of membrane protein functions by the fluidity, which was further corroborated by the increased bilayer fluidity and enzyme activity in benzyl alcohol treated basal membrane in each gestational age group.
人胎盘合体滋养层基底膜在整个妊娠期母体向发育中胎儿的营养物质转运过程中发挥着重要作用。膜脂质组成连同双层流动性被发现是调节这些转运过程的主要指标。在本研究中，研究了脂质组成变化对胎盘基底膜流动性的影响，以及随着妊娠进展，后者对膜酶和转运功能的调节作用。使用1,6 - 二苯基 - 1,3,5 - 己三烯作为探针的稳态荧光分析表明，标记的天然膜囊泡和由从基底膜囊泡中提取的脂质制备的脂质体的荧光各向异性均降低，这表明随着妊娠进展双层流动性增加。这反过来又成功地与胎盘发育过程中胆固醇含量的降低、磷脂浓度的增加以及胆固醇/磷脂比的稳步下降相关。随着妊娠进展，基底膜上增强的Na⁺ - K⁺ - ATP酶活性和稳态葡萄糖摄取表明流动性对膜蛋白功能的调节，这在每个妊娠年龄组中苄醇处理的基底膜中双层流动性和酶活性的增加中得到了进一步证实。
