Placental amino acid transport.
Moe, Aaron J.
The Edward Mallinkrodt Department of Pediatrics, Children's
Hospital, Washington University School of Medicine, St. Louis, MO
63110
APStracts 2:0145C, 1995.
Normal fetal growth and development depends on a continuous supply of
amino acids from the mother to the fetus. The placenta is responsible
for the transfer of amino acids between the two circulations. The
human placenta is hemomonochoriol meaning that the maternal and fetal
circulations are separated by a single layer of polarized epithelium
called the syncytiotrophoblast which is in direct contact with
maternal blood. Transport proteins located in the microvillous and
basal membrane of the syncytiotrophoblast are the principle mechanism
for transfer from maternal blood to fetal blood. Knowledge of the
function and regulation of syncytiotrophoblast amino acid
transporters is of great importance in understanding the mechanism of
placental transport and potentially improving fetal and newborn
outcomes. The development of methods for the isolation of
microvillous and basal membrane vesicles from human placenta over the
past two decades has contributed greatly to this understanding. Now a
primary cultured trophoblast model is available to study amino acid
transport and regulation as the cells differentiate. The types of
amino acid transporters and their distribution between the
syncytiotrophoblast microvillous and basal membranes is somewhat
unique compared to other polarized epithelium. These differences may
reflect the unusual circumstance of this epithelium which is exposed
to blood on both sides. The current state of knowledge as to the
types of transport systems present in syncytiotrophoblast, their
regulation, and the effects of maternal consumption of drugs on
transport will be discussed.
Received 1 June 1994; accepted in final form 7 October 1994.
APS Manuscript Number C619-4.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 28 March 1995.