Are individuals with glutathione S-transferase GSTT1 null genotype more susceptible to in vitro oxidative damage?

Recent epidemiological studies proposed that glutathione S-transferase (GST ) Ti null genotype was correlated with an increased susceptibility to disea ses associated with oxidative stress, including cancer. A comparative study using erythrocytes from individuals with GSTT1 null genotype was carried o ut to determine how resistance to oxidative stress is affected by lack of t his gene, and whether the CST status of a person is an important factor in risk toward oxidant chemicals. Malondialdehyde and carbonyl levels and fluo rescence and chemiluminescence formation were used as biomarkers of oxidati ve stress in erythrocytes exposed in vitro to cumene hydroperoxide (CumOOH) , an oxidizing agent. When peroxidation-dependent changes in these paramete rs were compared between GSTT1 null genotype and controls, who are both GST M1 and GSTT1 positive, no significant differences were found between the tw o genotypes, although the erythrocytes of the GSTT1 null group had lower GS TT1 activity toward CumOOH. Our results indicate that erythrocytes from ind ividuals with GSTT1 null genotype are not abnormally susceptible to CumOOH- induced oxidant challenge.