FIG. 2.

Effects of CsA and FK506 on activity of efflux transporters. (A and B) Cells were exposed to [³H]-TA in standard buffer for 30 min to induce intracellular accumulation of TA and then incubated with different concentrations of either CsA or FK506 for 2 h (A) or different time points (0–6 h) (B). Bile canaliculi were disrupted by additional 5-min incubation with Ca²⁺- and Mg²⁺-free buffer. TA efflux was determined by measuring intracellular TA accumulation. Efflux of TA was expressed relative to the level found in untreated cells, arbitrarily set at a value of 100%. (C) Cells were treated with either CsA or FK506 for 2 h. MRP2 activity was estimated using CDF, a specific substrate; nuclei were stained in blue using Hoechst dye. (D) HepaRG cells were treated with either CsA or FK506 at different concentrations for different time points (0–24 h) and then incubated with [³H]-TA for 30 min. NTCP activity was evaluated by measurement of intracellular accumulation of [³H]–TA. Data represent the means ± SD of three independent experiments. *p < 0.05, **p < 0.01, ***p < 0.001 compared with untreated cells, ^#p < 0.05, ^##p < 0.01 compared with CsA (same concentration) after 2 h.