FIGURE 7.

Effects of ABC transporter inhibitors on the ATP-dependent transport of S1P into IOVs. A, IOVs were preincubated with 1 μm [³³P]S1P in the presence of 100 μm glyburide, 20 μm MK571, and 10 μm cyclosporine A or 1 mm vanadate at 37 °C for 5 min and then incubated in the presence or absence of 2 mm ATP at 37 °C for 20 min. S1P uptake was expressed as the difference between the S1P amounts in the presence and absence of ATP. B, experiments were performed as described above except that 1 μm [³H]cGMP was used as the substrate instead of [³³P]S1P.