IL-1beta decreases SNAT1 and SNAT2 mRNA levels in trophoblasts, which is associated with a decrease in system A-mediated transport activity at the functional level. These findings may have important consequences under both physiologic conditions and pathologic conditions during pregnancy that are associated with elevated levels of IL-1beta.
ABSTRACT. To characterize the active transport of amino acids across the placenta, uptakes of proline, leucine, and alanine were kinetically examined in placental microvillous membrane vesicles (PMV) prepared from rats in the late gestational period. Uptake rates of these amino acids in PMV showed saturable hyperbolic curves that obeyed Michaelis-Menten kinetics. Proline, leucine, and alanine transport were demonstrated to be carrier mediated systems with sodium-dependent, -independent, and both manner, respectively. In addition, sodium-dependent L-alanine transport showed two different systems, and new sodium-independent alanine transport system (K m of 1.12 mM) was observed in rat placenta. From these results, rat placenta has carrier mediated amino acid transport systems, and posseses at least three different transport systems for alanine. -KEY WORDS: alanine, leucine, placental microvillous membrane vesicle (PMV), proline, transport.
ABSTRACT. Pregnant rats were subcutaneously administered with mouse epidermal growth factor (EGF) at the concentration of 0, 100, or 200 µg/kg body weight/day from day 18 to 21 of gestation. The amino acid analysis by high-performance liquid chromatography demonstrated that the umbilical venous/maternal and fetal/maternal ratio of serum proline concentration increased in EGF dose-dependent manner accompanied by the increase in the ratios of total fetal weight and placental weight to maternal body weight gain. These results suggested that EGF regulates fetal growth by, as one of its possible mechanism, promoting placental proline supply from mother to fetus. -KEY WORDS: epidermal growth factor (EGF), fetus, serum amino acid.
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