Cells, equilibrated in either Na⁺ or Li⁺ medium, were incubated with 100 nM NBMPR for 15 min and then incubated with 10 μM [³H]formycin B ± 50 μM gemcitabine (“Gem”) as shown in Fig. 6. The maximum accumulation of [³H]formycin B achieved over the 5 minute course of the assay (“Maximum”) and the initial rate of influx (V_i) were derived by extrapolation of hyperbolic curves fitted to these data. Each value represents the mean ± S.E. from five experiments.

↵3-a Significantly different from the corresponding data obtained in the absence of gemcitabine (Student’s t test, P < .05).