FIGURE 2.

Cellular accumulation of [³H]penciclovir (A), [³H]para-aminohippurate (B), [³H]estrone-3-sulfate (C), or [¹⁴C]glutarate (D) by parental CHO, HEK, or MDCK cells, or CHO, HEK, or MDCK cells stably expressing either OAT2-tv1 or OAT2-tv2. The concentration of [³H]penciclovir in the transport solution was 0.1 μM for CHO and MDCK cell experiments, and 0.5 μM for HEK cell experiments. The concentrations of [³H]para-aminohippurate, [³H]estrone-3-sulfate and [¹⁴C]glutarate were 8 nM, 10 nM, and 18 μM, respectively. Uptake was conducted for 5 min at room temperature. Values are mean ± standard error of the mean of four experiments. *Significantly different from parental cells, P < 0.05, two-tailed unpaired student’s t-test.