Increase in fluidity of human placental syncytiotrophoblastic brush-border membrane with advancement of gestational age: a fluorescence polarization study.

The syncytiotrophoblastic brush-border membrane (BBM) of human placenta plays a vital role in the exchange of metabolites between mother and developing fetus. The fluidity of this membrane renders its selective permeable character. To meet the changing needs of the growing fetus with the progress of gestational age changes in the composition and properties of BBM occur. In the present study, decrease in cholesterol/phospholipid ratio of BBM indicated an increase in fluidity with advancement of gestational age. Measurement of the steady state fluorescence anisotropy of labeled liposomes prepared from lipid extract of BBM as well as that of labeled BBM vesicles prepared from native BBM shows decrease in restriction of the bound dye molecule with increased gestational age. Decrease in transition temperature of BBM and enhanced glucose transport through it have been observed with advancement of pregnancy.