Figure 5

Accumulation and retention of free troxacitabine (trox) (a) and troxacitabine-nucleotides (b) in the HEK, HEK/MRP4 (HEK/4) and HEK/MRP5i (HEK/5) cell lines. T = 4: 4 hours exposure to 10 μM troxacitabine, T = 4 + 2: 4 hours exposure to troxacitabine followed by 2 hours drug-free medium. Values represent fmol/μg protein ± SEM of 3 separate experiments. For free troxacitabine the effect of drug-free medium was significant (*,p < 0.01) (paired t test). Accumulation was measured in the absence of indomethacin or probenecid.