FIGURE 5.

Multidrug resistance protein (MRP) 1/4 inhibitor MK-571 blunts DHA-induced GSSG efflux. (A) Erythrocytes (n = 5) were incubated with 2 mM DHA in the absence (orange) or presence (red) of 100 μM of the multidrug resistance protein (MRP1/4) inhibitor MK-571 for 15 min at RT. Control incubations were performed in PBS (black). Cells were then washed and further incubated in PBS (black and orange) or PBS containing 100 μM MK-571 (red). Abundance of GSSG in the supernatant was assessed at indicated timepoints by an enzymatic assay, as described in the section “Materials and Methods”. (B) Erythrocytes (n = 5) were treated with 2 mM DHA and various concentrations of MK-571 for 15 min at RT. After incubation, cells were washed and further incubated in PBS containing the respective concentrations of MK-571 for 90 min. GSSG efflux data were normalized to respective controls (pre-treatment with 2 mM DHA in PBS - 100%; PBS control cells - 0%, respectively).