GSH, NADPH, 5,5′-dithiobis (2-nitrobenzoic acid), diethyl maleate
(DEM), D,L-buthionine sulfoximine (BSO), GSH reductase, fetal
bovine serum (FBS), and TBH were purchased from Sigma Chemical (St.
Louis, MO). Dulbecco’s minimal essential medium (DMEM) was purchased
from Mediatech’s Cellgro (Tustin, CA).[ 32P]-dCTP (3000 Ci/mM) was purchased from New
England Nuclear–Du Pont (Boston, MA). Messenger RNA isolation kit
(Fast Track 2.0) was obtained from Invitrogen (Carlsbad, CA). All other
reagents were of analytical grade and were obtained from commercial
sources.