Effect of DTT on GSH uptake in side-sorted membrane vesicles from control and Oatp1-expressing HeLa cells.
| GSH | DTT (5 mM) | GSH Uptake | |||||||
|---|---|---|---|---|---|---|---|---|---|
| IO LPM | RO LPM | ||||||||
| Control Prep | Oatp1 Prep | Control Prep | Oatp1 Prep | ||||||
| 1 | 2 | 3 | 4 | 1 | 2 | 3 | 4 | ||
| nmol/mg of protein/10 s | |||||||||
| 1 mM | − | 2.14 | 1.86 | 3.28 | 3.16 | 2.37 | 1.77 | 2.98 | 2.56 |
| + | 2.62 | 1.72 | 3.48 | 2.31 | 1.34 | 0.76 | 2.15 | 1.49 | |
| 5 mM | − | 7.93 | 2.65 | 11.2 | 5.15 | 6.94 | 4.90 | 10.1 | 11.3 |
| + | 13.6 | 2.82 | 18.8 | 7.21 | 0.81 | 1.27 | 3.06 | 4.84 | |
Transport of GSH in untreated and DTT-pretreated inside-out (IO) and rightside-out (RO) membrane vesicles (LPM) from control and Oatp1-expressing HeLa cells was determined at various levels of GSH under a voltage-clamped condition as described under Materials and Methods. IO and RO membranes were prepared from each of four cell preparations. The average values of duplicate measurements in two individual preparations from control and Oatp1 expressing cells are shown. IO preparations 1 and 3 were 80 and 85% inside-out whereas preparations 2 and 4 were 65% inside-out. RO preparations were all 80 to 85% rightside-out.