l-Serine Uptake by Human Placental Microvillous Membrane Vesicles

Placenta ◽  
2007 ◽  
Vol 28 (5-6) ◽  
pp. 445-452 ◽  
Author(s):  
R.M. Lewis ◽  
J. Glazier ◽  
S.L. Greenwood ◽  
E.J. Bennett ◽  
K.M. Godfrey ◽  
...  
Keyword(s):  
Membrane Vesicles ◽  
Microvillous Membrane Vesicles

Biotin transport in microvillous membrane vesicles, cultured trophoblasts, and isolated perfused human placenta

1992 ◽  
Vol 262 (2) ◽  
pp. C302-C308 ◽  
Author(s):  
P. I. Karl ◽  
S. E. Fisher
Keyword(s):  
Membrane Potential ◽  
Growth And Development ◽  
Membrane Vesicles ◽  
Tissue Analysis ◽  
Michaelis Constant ◽  
Fetal Circulation ◽  
Maximal Stimulation ◽  
Placental Transport ◽  
Biotin Molecule ◽  
Microvillous Membrane Vesicles

Biotin, essential for normal fetal growth and development, must be transported across the placenta to reach the fetus. This study evaluated placental transport of biotin using microvillous membrane vesicles (MMV), cultured trophoblasts, and isolated perfused cotyledon. Biotin uptake in MMV was stimulated by an inward Na+ gradient. In the presence of Na+, maximal stimulation was observed with Cl-, among various anions. Biotin uptake required 1 Na+ per biotin molecule. Kinetic analysis in MMV showed saturable transport with a Michaelis constant (Km) of 26.1 +/- 2.9 microM. Increases in membrane potential did not alter biotin uptake. Biotin uptake by cultured trophoblasts was also stimulated in the presence of Na+ and was saturable (Km = 7.0 +/- 1.5 microM). In the perfused placental cotyledon, maternal-to-fetal (M-to-F) biotin transfer was not saturable. However, biotin transfer in the M-to-F direction was significantly greater than the reverse. When the fetal circulation was closed to allow accumulation, an F/M ratio of only 1.056:1 was achieved. Tissue analysis of biotin contents suggested an active accumulation within the placental compartment. This study demonstrates that biotin is actively transported into the placenta, across the microvillous membrane, and released into the fetal compartment at a slower rate.

Comparison of l-serine uptake by human placental microvillous membrane vesicles and placental villous fragments

Placenta ◽  
2010 ◽  
Vol 31 (5) ◽  
pp. 456-459 ◽  
Author(s):  
A.P. Brand ◽  
S.L. Greenwood ◽  
J.D. Glazier ◽  
E.J. Bennett ◽  
K.M. Godfrey ◽  
...  
Keyword(s):  
Membrane Vesicles ◽  
Microvillous Membrane Vesicles

Cocaine inhibits alanine uptake by human placental microvillous membrane vesicles

1993 ◽  
Vol 169 (3) ◽  
pp. 515-521 ◽  
Author(s):  
Jeffrey M. Dicke ◽  
Deborah K. Verges ◽  
Kenneth L. Polakoski
Keyword(s):  
Membrane Vesicles ◽  
Microvillous Membrane Vesicles

scholarly journals Proline Uptake into Equine Placental Microvillous Membrane Vesicles.

1999 ◽  
Vol 10 (1) ◽  
pp. 21-25
Author(s):  
Boonrit THONGSONG ◽  
Kazutaka MUKAI ◽  
Makoto BONKOBARA ◽  
Tsuyoshi UCHIDE ◽  
Hiroyuki OGAWA ◽  
...  
Keyword(s):  
Membrane Vesicles ◽  
Microvillous Membrane Vesicles

The Mechanism of Human Placental Urea Transport: A Study Using Placental Brush Border (Microvillous) Membrane Vesicles

2010 ◽  
Vol 17 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Hiroyasu Hisanaga ◽  
Hideaki Iioka ◽  
Ikuko Moriyama ◽  
Kaoru Nabuchi ◽  
Keiko Morimoto ◽  
...  
Keyword(s):  
Brush Border ◽  
Membrane Vesicles ◽  
Urea Transport ◽  
Microvillous Membrane Vesicles

Chloride transport by human placental microvillous membrane vesicles

1993 ◽  
Vol 1153 (1) ◽  
pp. 122-126 ◽  
Author(s):  
Steven Byrne ◽  
Jocelyn D. Glazier ◽  
Susan L. Greenwood ◽  
Dhushy Mahendran ◽  
Colin P. Sibley
Keyword(s):  
Chloride Transport ◽  
Membrane Vesicles ◽  
Microvillous Membrane Vesicles
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