FIGURE 4.
Determination of GSH apparent half-life (appT1/2GSH). Cells grown under standard conditions were labeled with [35S]GSH for 30–40 min, washed, and suspended either in nonradioactive standard medium or sulfur-free medium. The same amount of culture was regularly collected and processed to extract MF and PF. A, shown is autoradiography (left panel) and the corresponding quantifications (right panel) of the 35S-labeled metabolites separated by TLC. Time of collection (min) is indicated below each lane. The arrow indicates [35S]GSH spots. GSH is the sole radioactive metabolite that is detectable under these conditions. [35S]GSH radioactivity at time 0 is set to 100%. B, shown is evolution of the radioactivity in MF (black diamonds) and PF (asterisks) of representative experiments. Values are relative to total radioactivity.