Thermal acclimation, hydroperoxide detoxifying enzymes and oxidative stress in the lung and liver of Rana perezi

1. 1.Rana perezi adult frogs were acclimated to cold (10 ± 2°C) and warm (29 ± 1°C) temperatures for 4 months.

2. 2.After acclimation, a partial compensation of the oxygen consumption of the animals was found because of a reduction of its thermal sensitivity.

3. 3.Activities of liver and lung catalase, selenium (Se)-dependent and Se-independent glutathione peroxidases were not changed by thermal acclimation.

4. 4.Tissue peroxidation (TBA-RS) increased in the liver of heat acclimated animals.

5. 5.Hydroperoxide detoxifying enzyme activities did not show inverse compensation of temperature during acclimation. It is proposed that the pattern of thermal compensation shown by these enzymes in different species depends on a variety of factors including: (a) the thermal sensitivities of hydroperoxide producing and scavenging systems; (b) the changes induced by acclimation in the rate of hydroperoxide generation.

Author Keywords: Temperature acclimation; thermal compensation; oxygen radicals; hydroperoxides; catalase; glutathione peroxidase; lipid peroxidation; oxygen consumption; hydrogen peroxide; oxidative stress; free radicals; frog; acclimation; compensation; detoxifying enzymes; Rana perezi