System A amino acid transporter activity in term placenta is substrate specific and inversely related to amino acid concentration

来自 EBSCO

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作者：

M Snook Parrott，F Von Versen-Hoeynck，RB Ness，N Markovic，JM Roberts

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摘要：

Using intact villous fragments from normal term placentas, the authors characterize the effect of reduced amino acid availability on amino acid uptake via the system A amino acid transporter. Villous fragments deprived of amino acids demonstrate increased system A activity compared with those incubated in an amino acid-sufficient medium (P < .05). Similarly, placental villous fragments exposed to media containing only amino acids not specifically transported by system A have a significant increase in system A activity compared with villous fragments incubated in an amino acid-sufficient medium containing only substrates of system A (P < .05). There is a significant trend for increasing system A activity as the concentrations of the system A amino acid substrates are decreased (P < .01). Collectively, these data indicate that normal placentas can increase system A amino acid transporter activity in a substrate-specific and dose-dependent manner as a means to ensure optimal fetal growth in the presence of amino acid limitation.

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关键词：

placental villous fragments amino acid uptake regulation system A amino acid starvation

DOI：

10.1177/1933719107306895

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年份：

2007