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Uridine transport in human erythrocytes: data from normal subjects and from patients with renal failure
Author(s) -
Fervenza FC,
Meredith D,
Ellory JC,
Hendry BM
Publication year - 1991
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.1991.sp003480
Subject(s) - uridine , nucleoside , nucleoside transporter , chemistry , medicine , endocrinology , kinetics , thymidine , metabolism , biochemistry , transporter , biology , rna , in vitro , gene , quantum mechanics , physics
Erythrocyte uridine transport has been studied in eight normal individuals and eight patients on haemodialysis for chronic renal failure. The initial rate of zero‐trans uridine influx at 37 degrees C has been measured as a function of extracellular uridine concentration using [14C]‐labelled uridine. The results are consistent with Michaelis‐Menten kinetics. In normal humans the mean Vmax for uridine influx was 32.8 +/‐ 6.4 mumol (1 cells)‐1 s‐1 (mean +/‐ S.D.) and the mean Km was 190 +/‐ 12.3 microM. The measurements made in renal failure patients were not significantly different (mean Vmax 30.1 +/‐ 7.1 mumol (1 cells)‐1 s‐1, mean Km, 185 +/‐ 13.2 microM). These results are discussed with reference to the reported data on uridine transport in human erythrocytes at temperatures between 4 and 35 degrees C; it is suggested that zero‐trans uridine influx shows a decrease in temperature dependence above 25 degrees C. The Vmax for zero‐trans uridine influx at 37 degrees C in normal erythrocytes represents a turnover number for the nucleoside transporter of 180 uridine molecules per second.