[HTML][HTML] Nucleoside transport in human colonic epithelial cell lines: evidence for two Na+-independent transport systems in T84 and Caco-2 cells

JL Ward, CM Tse - Biochimica et Biophysica Acta (BBA)-Biomembranes, 1999 - Elsevier
JL Ward, CM Tse
Biochimica et Biophysica Acta (BBA)-Biomembranes, 1999Elsevier
RT-PCR of RNA isolated from monolayers of the human colonic epithelial cell lines T84 and
Caco-2 demonstrated the presence of mRNA for the two cloned Na+-independent
equilibrative nucleoside transporters, ENT1 and ENT2, but not for the cloned Na+-
dependent concentrative nucleoside transporters, CNT1 and CNT2. Uptake of [3H] uridine
by cell monolayers in balanced Na+-containing and Na+-free media confirmed the presence
of only Na+-independent nucleoside transport mechanisms. This uptake was decreased by …
RT-PCR of RNA isolated from monolayers of the human colonic epithelial cell lines T84 and Caco-2 demonstrated the presence of mRNA for the two cloned Na+-independent equilibrative nucleoside transporters, ENT1 and ENT2, but not for the cloned Na+-dependent concentrative nucleoside transporters, CNT1 and CNT2. Uptake of [3H]uridine by cell monolayers in balanced Na+-containing and Na+-free media confirmed the presence of only Na+-independent nucleoside transport mechanisms. This uptake was decreased by 70–75% in the presence of 1 μM nitrobenzylthioinosine, a concentration that completely inhibits ENT1, and was completely blocked by the addition of 10 μM dipyridamole, a concentration that inhibits both ENT1 and ENT2. These findings indicate the presence in T84 and Caco-2 cells of two functional Na+-independent equilibrative nucleoside transporters, ENT1 and ENT2.
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