Changes in catalase and glutathione peroxidase activities in wild-type and acatalasemic mice. (A) Lung catalase activity is decreased after bleomycin administration in wild-type (C3H/AnLCsaCsa), whereas it is less than 10% in acatalasemic mice at any time point. (B) In the lungs of untreated acatalasemic mice glutathione peroxidase activity is higher compared with wild-type mice, although no further increase is observed following bleomycin administration. Day 0; untreated, Day 7; 7 days after bleomycin administration, Day 14; 14 days after bleomycin administration. *; p < 0.05 vs. Day 0.