[Studies on L-glutamate transport mechanism in human placental trophoblast microvilli membrane vesicles]

Nihon Sanka Fujinka Gakkai Zasshi. 1985 Feb;37(2):207-12.
[Article in Japanese]

Abstract

The uptake of L-glutamate in brush border (microvilli) vesicles prepared from human term placenta was studied using the rapid filtration technique. The uptake of L-glutamate into the vesicles occurred osmotically, and preincubation with L-glutamate increased the uptake of amino acid. These findings indicate that the uptake of L-glutamate by placental trophoblast brush border membranes represents the transport into membrane vesicles. A Na+ electrochemical gradient (extravesicular greater than intravesicular) stimulated the initial rate of L-glutamate uptake about three times. The initial rate of transport exhibited saturation kinetics with respect to the L-glutamate concentration; an apparent Km of 0.15 mM and V max of 70 pmol/mg protein in 20 seconds were calculated. The uptake of L-glutamate into the vesicles was competitively inhibited by L-glutamate and L-cysteate (acidic amino acid). These results indicate that a Na-dependent acidic amino acid specific transport system exists in the placental trophoblast microvilli membrane. These results indicate that the transport of L-glutamate across the placental microvilli membrane is sodium-dependent and carrier mediated.

Publication types

  • English Abstract

MeSH terms

  • Aspartic Acid / pharmacology
  • Biological Transport
  • Cells, Cultured
  • Female
  • Glutamates / metabolism*
  • Humans
  • Ions
  • Maternal-Fetal Exchange
  • Microvilli / metabolism
  • Organoids / metabolism
  • Pregnancy
  • Sodium / metabolism
  • Trophoblasts / metabolism*

Substances

  • Glutamates
  • Ions
  • Aspartic Acid
  • Sodium