Superoxide dismutases (SODs) represent the first line of antioxidant defense and
any alternation in their function might be potentially damaging. Therefore, changes
of the CuZnSOD activity in cytosolic and nuclear fractions and MnSOD activity in
mitochondrial fraction in liver of male rats exposed to 2h of either immobilization
(IM) or cold (4°) as acute stressors, 21 day of social isolation (IS) as chronic stress,
or their combination (acute+chronic stress), were investigated. Serum
corticosterone (CORT) level was monitored as a stress marker. Acute stress IM
with elevated CORT level led to increased CuZnSOD activity in nuclear fraction.
Chronic isolation, where CORT was close to control value did not change the
CuZnSOD activity neither in nuclei nor cytosol fraction, while combined stress
IS+Cold led to increased cytosolic CuZnSOD activity. MnSOD activity in
mitochondrial fraction was decreased in all treated groups. Data indicate that
unchanged or increased cytosolic or nuclear CuZnSOD activity after different
stressors mediate liver restoration of homeostasis, while decrease of mitochondrial
MnSOD activity may results in cellular injury and inefficient ROS defense
