Fig. 4.
Inhibition constant (Ki) determination for select organic anions in the CHO-mOat6 and CHO-mOat3 cell lines. One-minute uptake of [3H]ES (1 μM) in CHO-mOat3 cells (■) was measured in the presence of increasing concentrations (10−8 to 10−2 M) of probenecid, salicylate, 2,4-D, penicillin G, 5-HIAA, HVA, DOPAC, HA, and DHEAS. Two-minute uptake of [3H]ES (5 μM) in CHO-mOat6 cells (▴) was measured in the presence of increasing concentrations (10−7 to 10−3 M) of 5-HIAA, HVA, DOPAC, HA, and DHEAS. Data were corrected for nonspecific background measured in the CHO-FRT (control) cells before kinetic analysis. Ki values were determined by using nonlinear regression and the “one-site competition” model in Prism software. Experiments were repeated three times in triplicate with the mean Ki ± S.E. reported in Table 1. Graphs shown are mean ± S.E. (n = 3) from representative experiments.