A new form of asymmetry in epithelia: kinetics of apical and basal sulphate transport in human placenta.
Sulphate transport into and out of membrane vesicles prepared from both the brush-border and basal surfaces of the human placental trophoblast has been studied. For both surfaces of this epithelium clear evidence of trans-stimulation of influx is seen but for efflux, acceleration of labelled sulphate movement by addition of external sulphate is seen only in basal and not in brush-border membrane vesicles. This kinetic asymmetry may underlie the previously observed, but unexplained, finding that the concentration of sulphate is greater in the fetal than in the maternal circulation.
Bustamante
J C
JC
Department of Physiology, King's College, London.
Yudilevich
D L
DL
Boyd
C A
CA
D001693:Biological Transport, Active; D004848:Epithelium / Q000378:metabolism; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008431:Maternal-Fetal Exchange; D008871:Microvilli / Q000378:metabolism; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D013431:Sulfates / Q000378:metabolism*; D014327:Trophoblasts / Q000378:metabolism
D013431:Sulfates