Corrected cytosolic (Cyt), total cellular (TotCell) and ER (ER) levels, as indicated, of (A) [GSx] = [GSH] + 2[GSSG], (B) reduced [GSH] and (C) oxidized [GSSG] measured in HGT1 cells incubated with 30 μM GSH for the indicated time. (D) Non-reducing SDS-PAGE migration of ER-1-Cys-Grx1 (upper panel) and ER-rxYFP (lower panel) from lysates of HGT1 cells incubated with 30 μM GSH for the indicated time, representative of those used to derive the data in E. (E) The ER glutathione redox potential (EGSH.ER), and ER ratio of GSH/GSSG values used to derive the data in A–C. (F) Same as in A, but with 50 μM GSH. Values are the mean of three independent biological replicas ± standard deviation (s.d.).