Figure 6.

OATP2B1-mediated uptake of sulphasalazine in HEK293 cells. (A) The uptake of [³H]oestrone-3-sulphate (E3S; 0.1 nM) and sulphasalazine (0.1 µM) was determined in OATP2B1-expressing HEK293 cells and mock transfected cells (control) for 2 min at 37°C in the absence and presence of atorvastatin (ATV; 20 µM). Data shown are mean (±SEM) values (n= 3). **P < 0.01 (mock control vs. OATP2B1-HEK significantly different from control), ††P < 0.01 (significant effect of atorvastatin); one-way anova followed by Tukey's multiple comparison tests. (B) The uptake of sulphasalazine was determined in OATP2B1-HEK and mock transfected cells for 2 min at 37°C at various substrate concentrations (0.1, 0.3, 1.0, 3.0, 10, 30 and 100 µM). Specific uptake by OATP2B1 was obtained by subtracting the uptake by mock transfected cells from the uptake by OATP2B1-HEK. A calculated curve is shown.