Sodium-dependent and -independent transport of L-glutamate in the rat intestinal crypt-like cell line IEC-17.
Mechanisms of L-glutamate transport in intestinal crypts were investigated using the rat intestinal crypt-like cell line IEC-17. Kinetic analysis and competition experiments run in the presence or in the absence of extracellular sodium indicate that L-glutamate uptake occurs through three different transport components: (1) a high affinity Na+-independent component also carrying cystine, similar to system x(c)-; (2) a high affinity Na+-dependent component inhibited by D- and L-aspartate corresponding to the ubiquitous system X(A,G)-; and (3) a low affinity Na+-dependent system resembling the neutral amino acid transport system ASC. The simultaneous presence of these three components suggest that crypt cells are ready to face potential high variations of L-glutamate concentration in the intestinal villus environment.
Mordrelle
A
A
INRA, Laboratoire de Nutrition Humaine et Physiologie Intestinale, Institut National Agronomique Paris-Grignon, France.
Huneau
J F
JF
Tomé
D
D
D000818:Animals; D001692:Biological Transport; D002460:Cell Line; D018698:Glutamic Acid / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000166:cytology; D051381:Rats; D012964:Sodium / Q000378:metabolism*
D018698:Glutamic Acid; D012964:Sodium