Hypoxanthine enters human vascular endothelial cells (ECV 304) via the nitrobenzylthioinosine-insensitive equilibrative nucleoside transporter

Osses, N. and Pearson, J.D. and Yudilevich, D.L. and Jarvis, S.M. (1996) Hypoxanthine enters human vascular endothelial cells (ECV 304) via the nitrobenzylthioinosine-insensitive equilibrative nucleoside transporter. Biochemical Journal, 317 . pp. 843-848. ISSN 0264-6021. (The full text of this publication is not available from this repository)

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Abstract

The transport properties of the nucleobase hypoxanthine were examined in the human umbilical vein endothelial cell line ECV 304. Initial rates of hypoxanthine influx were independent of extracellular cations: replacement of Na+ with Li+, Rb+, N-methyl-D-glucamine or choline had no significant effect on hypoxanthine uptake by ECV 304 cells. Kinetic analysis demonstrated the presence of a single saturable system for the transport of hypoxanthine in ECV 304 cells with an apparent K-m of 320+/-10 mu M and a V-max of 5.6+/-0.9 pmol/10(6) cells per s. Hypoxanthine uptake was inhibited by the nucleosides adenosine, uridine and thymidine (apparent K-i 41+/-6, 240+/-27 and 59+/-8 mu M respectively) and the nucleoside transport inhibitors nitrobenzylthioinosine (NBMPR), dilazep and dipyridamole (apparent K-i 2.5+/-0.3, 11+/-3 and 0.16+/-0.006 mu M respectively), whereas the nucleobases adenine, guanine and thymine had little effect (50% inhibition at >1 mM). ECV 304 cells were also shown to transport adenosine via both the NBMPR-sensitive and -insensitive nucleoside carriers. Hypoxanthine specifically inhibited adenosine transport via the NBMPR-insensitive system in a competitive manner (apparent K-i 290+/-14 mu M). These results indicate that hypoxanthine entry into ECV 304 endothelial cells is mediated by the NBMPR-insensitive nucleoside carrier present in these cells.

Item Type: Article
Additional information: Part 3
Subjects: Q Science > QP Physiology (Living systems) > QP517 Biochemistry
Q Science > QP Physiology (Living systems) > QP506 Molecular biology
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences
Depositing User: F.D. Zabet
Date Deposited: 10 Jun 2009 16:48
Last Modified: 10 Jun 2009 16:48
Resource URI: http://kar.kent.ac.uk/id/eprint/18711 (The current URI for this page, for reference purposes)
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