title: Neutral amino acid influx in developing rabbit blastocysts.
abstract: The influx of the neutral amino acids glycine, aminoisobutyric acid (AIB), and leucine into rabbit blastocysts was measured. In day 6 postcoitus (pc) embryos, glycine influx was Na+ independent, whereas AIB and leucine influx involved both Na+-dependent and independent components. From days 5 to 7 pc, the leucine and AIB influx remained constant, although the Na+-dependent fraction decreased and the Na+-independent fraction increased with age. None of the Na+-independent influx was inhibited by methylaminoisobutyric acid (MeAIB), an amino acid analogue specific for the system A of neutral amino acid uptake. In addition, MeAIB influx was Na+ independent, implying that system A is not involved in leucine or AIB uptake. All Na+-dependent influx is thus considered to occur via system ASC. System L contributed only to the influx of leucine at days 6 and 7 pc, as measured by inhibition of Na+-independent influx by 2-amino-bicyclo-(2,2,1)-heptane-2-carboxylic acid.
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000621:Aminoisobutyric Acids / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001693:Biological Transport, Active; D001755:Blastocyst / Q000378:metabolism*; D005260:Female; D005998:Glycine / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism*; D007930:Leucine / Q000378:metabolism; D011247:Pregnancy; D011817:Rabbits; D013997:Time Factors
chemical_list: D000596:Amino Acids; D000621:Aminoisobutyric Acids; D007473:Ion Channels; C017911:2-(methylamino)isobutyric acid; D007930:Leucine; D005998:Glycine