Figure 3.

P-gp activity was assessed using R123 accumulation in LS180 and Caco-2 cells. Cells were pretreated with 20 μM budesonide or vehicle for 72 h. Rifampicin was used as a positive control for P-gp induction. Data represent R123 fluorescence normalized to verapamil-treated cells. A decrease in intracellular fluorescence is indicative of an increase in P-gp activity and vice versa. Results are expressed as mean±s.e.m. (n=3–4). ^**P<0.01, ^***P<0.001 vs control cells.