Nucleoside Transport in Cultured Llc-Pk1 Epithelia

Griffith, D.A. and Doherty, A.J. and Jarvis, S.M. (1992) Nucleoside Transport in Cultured Llc-Pk1 Epithelia. Biochimica Et Biophysica Acta, 1106 (2). pp. 303-310. ISSN 0006-3002. (The full text of this publication is not available from this repository)

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Abstract

The transport of nucleosides by LLC-PK1 cells, a continuous epithelial cell line derived from pig kidney, was characterised. Uridine influx was saturable (apparent K(m) approximately 34-mu-M at 22-degrees-C) and inhibited by > 95% by nitrobenzylthioinosine (NBMPR), dilazep and a variety of purine and pyrimidine nucleosides. In contrast to other cultured animal cells, the NBMPR-sensitive nucleoside transporter in LLC-PK1 cells exhibited both a high affinity for cytidine (apparent K(i) approximately 65-mu-M for influx) and differential 'mobility' of the carrier (the kinetic parameters of equilibrium exchange of formycin B are greater than those for formycin B influx). An additional minor component of sodium-dependent uridine influx in LLC-PK, cells became detectable when the NBMPR-sensitive nucleoside transporter was blocked by the presence of 10-mu-M NBMPR. This active transport system was inhibited by adenosine, inosine and guanosine but thymidine and cytidine were without effect, inhibition properties identical to the N1 sodium-dependent nucleoside carrier in bovine renal outer cortical brush-border membrane vesicles (Williams and Jarvis (1991) Biochem. J. 274, 27-33). Late proximal tubule brush-border membrane vesicles of porcine kidney were shown to have a much reduced Na+-dependent uridine uptake activity compared to early proximal tubule porcine brush-border membrane vesicles. These results, together with the recent suggestion of thc late proximal tubular origin of LLC-PK1 cells, suggest that in vivo nucleoside transport across thc late proximal tubule cell may proceed mainly via a facilitated-diffusion process.

Item Type: Article
Uncontrolled keywords: Nucleoside Transport; Facilitated Transport; Active Transport; Nitrobenzylthioinosine; Llc-Pk1 Epithelium; (Pig Kidney Brush-Border Vesicle)
Subjects: Q Science > QP Physiology (Living systems) > QP517 Biochemistry
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences
Depositing User: P. Ogbuji
Date Deposited: 07 Sep 2009 08:09
Last Modified: 12 Jun 2012 10:31
Resource URI: http://kar.kent.ac.uk/id/eprint/22591 (The current URI for this page, for reference purposes)
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