Na(+)-dependent high affinity uptake of L-glutamate in primary cultures of human fibroblasts isolated from three different types of tissue.
Cultured human fibroblasts isolated from embryonic muscle, skin and peripheral nerve tissues were found to accumulate [3H]L-glutamate by a Na(+)-dependent uptake process strongly inhibited by several glutamate/aspartate analogues including D- and L-aspartate, D- and L-threo-3-hydroxyaspartate and L-trans-pyrrolidine-2,4-dicarboxylate but not D-glutamate. It was also reduced by elevated concentrations of K+, Rb+ and Cs+. The values of Km's were 5-20 microM, well within the 'high affinity' region. Variations in the capacity (Vmax) of [3H]L-glutamate uptake did not correlate with the origin (muscle, skin or nerve tissue) of the fibroblasts. The uptake characteristics suggest that it is mediated by a transport system similar to that commonly observed only in brain tissue.
Balcar
V J
VJ
Department of Anatomy and Histology, University of Sydney, Australia.
Shen
J
J
Bao
S
S
King
N J
NJ
D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002478:Cells, Cultured; D003998:Dicarboxylic Acids / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism*; D005971:Glutamates / Q000378:metabolism* / Q000494:pharmacology; D018698:Glutamic Acid; D006801:Humans; D007700:Kinetics; D009132:Muscles / Q000196:embryology* / Q000378:metabolism; D010525:Peripheral Nerves / Q000378:metabolism*; D011759:Pyrrolidines / Q000494:pharmacology; D012867:Skin / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology*; D014316:Tritium
D003998:Dicarboxylic Acids; D005971:Glutamates; D011759:Pyrrolidines; D014316:Tritium; C011274:3-hydroxyaspartic acid; D001224:Aspartic Acid; D018698:Glutamic Acid; C083486:pyrrolidine-2,4-dicarboxylic acid; D012964:Sodium