Figure 2. Inhibitors of cellular GSH efflux attenuates STP-induced apoptosis.
HT29 cells were treated for 8h with 2μM STP without or with 30min pre-treatment with 10mM of each of the GSH transport inhibitors, γ-glutamyl glutamate (γGG) or ophthalmic acid (OPA). Total GSH in the extracellular media and cell apoptosis were determined at 8h and 24h, respectively, post STP treatment. A: Percent GSH efflux. B: Percent cell apoptosis. Results are mean ± S.E. for 4 separate experiments * p< 0.05 versus untreated control; # p< 0.05 versus STP alone. C: HT29 cells were treated with 2μM STP and cell apoptosis was determined at 24h. In some experiments, γGG (10mM) were added either at 30min before or at 8h post-STP treatment. Results are mean ± S.E. * p< 0.05 versus untreated control; # p< 0.05 versus STP alone, ° p< 0.05 versus 30min pretreatment with γ-GG before STP exposure.