Correlation between the anti-oxidant enzyme activities of blood fractions and the yield of bleomycin-induced chromosome damage.

The concentration of the anti-oxidant enzymes catalase (CAT), peroxidases (POD) and superoxide dismutases (SOD) in different blood fractions, and the chromosomal sensitivity of lymphocytes to bleomycin-induced free radicals (expressed as frequency of dicentrics per bleomycin dose) were analyzed in 10 normal human donors. Our results demonstrate that the physiological concentration of the enzymes as well as the chromosomal sensitivity exhibited a wide interindividual variability. An inverse correlation between chromosomal sensitivity to bleomycin and SOD concentration in whole blood, plasma and red cells was found. On the other hand, no correlation between the yield of bleomycin-induced dicentrics and the concentration of CAT or POD was detected in any of the blood fractions analyzed. These findings suggest that the concentration of SOD may play an important role in the cellular susceptibility to DNA damage by free radicals.