FIGURE 4.

DHA-dependent GSSG efflux from erythrocytes is rescued by glucose as well as 2-DG. (A) Erythrocytes (n = 7) were incubated with 2 mM DHA in the absence (orange) or presence (blue) of 5 mM glucose for 15 min at RT. Control incubations were carried out in PBS (black). Afterward, cells were washed and resuspended in PBS (black and orange) or PBS containing 5 mM glucose (blue). Aliquots were taken at indicated time points and GSSG concentrations in the supernatant enzymatically assessed as described in the section “Materials and Methods”. (B,C) Erythrocytes (n = 14) were treated with various amounts of DHA for 15 min at RT, washed and resuspended in PBS for 90 min. GSSG content in the supernatants was assessed and the efflux rates calculated. Data are given as mean values in percent after normalizing to control conditions (pre-treatment with 2 mM DHA in PBS - 100%; PBS control cells - 0%, respectively) (B), or in absolute values for individual experiments (C). (D) Erythrocytes (n = 14) were treated with 2 mM DHA in the presence of glucose (black) or 2-DG (gray) for 90 min at RT and the GSSG content in the supernatant assessed. GSSG efflux rates are given in percent after normalization to control conditions (pre-treatment with 2 mM DHA in PBS without glucose or 2-DG - 100%; PBS control cells - 0%, respectively).