Fig. 1.

Inhibitory effect of hydrochlorothiazide (HCTZ) on the uptake of probe substrates by renal transporters. Uptake of 5.5 μM metformin by human organic cation transporter 2 (hOCT2) and human multidrug and toxin extrusion proteins 1 and 2-K (hMATE1 and hMATE2-K, respectively), 1 μM [³H]p-aminohippurate (PAH) by human organic anion transporter 1 (hOAT1), and 0.06 μM [³H]estrone sulfate (ES) by human organic anion transporter 3 (hOAT3) in the absence (white bar) and presence of 500 μM HCTZ (black bar) and 2 mM HCTZ (gray bar) was measured in both transporter-expressing and control human embryonic kidney-293 cells. Transporter-specific uptake was obtained by subtracting uptake in control cells from uptake in transporter-expressing cells. Uptake was measured after a 2-min incubation at 37°C. Data are presented as means ± SD. *P < 0.05 and ***P < 0.001, uptake in the presence of HCTZ was significantly lower than that in the absence of HCTZ.