TABLE 1

Effects of extracellular compounds on uptakes of [3H]estrone-3-sulfate at pH 5.0 and pH 7.4 by OATP-B

OATP-B-cDNA-transfected or mock cells were preincubated for 20 min at 37°C in the suspension medium (pH 7.4). Uptake of [3H]estrone-3-sulfate (5.07 nM) over 1 or 5 min was measured at 37°C by incubating cells in the uptake medium at pH 5.0 or 7.4, respectively, and the results are shown as percentage of control uptake measured in the uptake medium (pH 5.0 or 7.4) after correcting for the uptake by mock cells. Each value represents the mean ± S.E.M. (n = 3 or 4). The control study on the effect of FCCP includes the ethanol (0.5 %) used to dissolve FCCP.



Uptake of [3H]Estrone-3-sulfate by OATP-B

pH 5.0
pH 7.4
% of control
Control 100.0 ± 4.6 100.0 ± 6.0
Na+-free 93.8 ± 2.4 85.7 ± 5.3
Cl--free 89.1 ± 2.4 106.0 ± 13.6
+ 10 mM GSH 110.8 ± 7.0 105.4 ± 7.3
+ 20 mM HCO3- 92.3 ± 5.0 97.3 ± 5.7
Control (0.5% ethanol) 100.0 ± 8.1 100.0 ± 10.8
+ 5 μM FCCP 69.2 ± 4.7* 85.3 ± 2.4
+ 20 μM FCCP
42.0 ± 8.6*
80.9 ± 5.7
  • * indicates a significant difference from the control (p < 0.05).