A possible effect of the Na+ concentration in oviductal fluid on amino acid uptake by cleavage-stage mouse embryos.
Two- and four-cell mouse embryos exhibited both Na+-dependent and Na+-independent components of zwitterionic alpha-amino acid transport, which we tentatively ascribe to the A and L amino acid transport systems, respectively. Uptake of taurine was virtually all Na+-dependent and is probably via the beta system. Na+-independent L-lysine uptake by two-cell embryos may have been via system y+. The small amount of lysine transport which was Na+-dependent (30% of the total) could not be attributed to any well known transport system and may have been due to the early ontogenetic expression of a newly described transport system which predominates in preimplantation blastocysts. We conclude that the rate of Na+-dependent amino acid transport in two-cell mouse embryos could be significantly affected in situ by changes in the [Na+] which are known to occur in oviductal fluid.
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001755:Blastocyst / Q000187:drug effects / Q000378:metabolism*; D003470:Culture Media; D005187:Fallopian Tubes / Q000502:physiology*; D005260:Female; D007700:Kinetics; D051379:Mice; D008813:Mice, Inbred ICR; D011247:Pregnancy; D012964:Sodium / Q000378:metabolism* / Q000494:pharmacology
D000596:Amino Acids; D003470:Culture Media; D012964:Sodium