Discrepancy between the different subcellular activities of rat liver catalase and superoxide dismutases in response...

After acute ethanol administration (2.3 g/kg) peroxisomal and extra-peroxisomal catalase activities were affected in opposite directions. As long as ethanol was present, peroxisomal catalase activity was enhanced, but unaffected by amino-triazole (AT) injection. Extra-peroxisomal catalase activity was decreased during the 24hr following ethanol administration and was also inhibited after AT injection. Whereas mitochondrial manganese-dependent superoxide dismutase (Mn-SOD) was unaffected, the cytosolic Cu,Zn-SOD activity was decreased. The time-course of this decrease suggests that acute ethanol administration affects primarily extra-peroxisomal catalase activity, thus rendering cytosolic superoxide dismutase more exposed to oxygen derivatives.