Seasonal changes in the antioxidative defense in ground squirrels (Citellus citellus): possible role of GSH-Px.
As seasonal hibernators, ground squirrels decrease their body temperature to 7 degrees C and hibernate during the winter. Maintenance at 30 degrees C prevents seasonal changes of body temperature and animals remain euthermic and active. We measured selenium (Se)-dependent glutathione peroxidase (GSH-Px), as well as the activity of other antioxidative components such as superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione-S-transferase (GST) and the amount of low-molecular-weight antioxidants glutathione (GSH), ascorbic acid (AsA), and vitamin E (vit E) in spring, summer, and winter in ground squirrels continuously kept at a temperature of 30 degrees C. We examined liver and interscapular brown adipose tissue (IBAT) as thermogenic tissues, as well as the brain and the kidneys. During the winter, we found a decrease in enzymatic activity and an increase in the level of low molecular antioxidants in all tissues. Correlation analysis revealed a similarity in the composition of antioxidative defense (AD) among the tissues examined. The results obtained clearly demonstrated numerous correlative expressions of antioxidative components in this experimental model, especially of GSH-Px, suggesting the complexity of the system responsible for the maintenance of physiological homeostasis.
Blagojević
D
D
Department of Physiology, Institute for Biological Research, Belgrade, Yugoslavia.
Buzadzić
B
B
Korać
B
B
Saicić
Z S
ZS
Radojicić
R
R
Spasić
M B
MB
Petrović
V M
VM
D002001:Adipose Tissue, Brown / Q000201:enzymology / Q000502:physiology; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001833:Body Temperature Regulation / Q000502:physiology; D001921:Brain / Q000201:enzymology / Q000502:physiology; D002374:Catalase / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism / Q000502:physiology*; D005982:Glutathione Transferase / Q000378:metabolism; D006605:Hibernation / Q000502:physiology; D007668:Kidney / Q000201:enzymology / Q000502:physiology; D008099:Liver / Q000201:enzymology / Q000502:physiology; D008297:Male; D051381:Rats; D012589:Sciuridae / Q000502:physiology*; D012621:Seasons; D012643:Selenium / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013696:Temperature
D000975:Antioxidants; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; D012643:Selenium