Investigation of Some Antioxidant Enzymes Activities Depending on Adrenomedullin Treatment and Cold Stress in Rat Liver Tissue

Purpose: The aim of this study is to investigate the compensating effects of adrenomedullin on liver tissue after cold stress treatment. Materials and Methods: Male Wistar rats were divided into four groups as control, adrenomedullin, cold stress and cold stress + adrenomedullin treated. Adrenomedullin was given by intraperitoneal injection (2 mg/g body weight) once a day for a week. For cold stress the rats were kept at 10 C for a week. Catalase, glutathione peroxidase and superoxide dismutase activities were measured in liver tissue. Results: Catalase activity was decreased significantly as compared to control in adrenomedullin treated group (p<0.05). There was no significant difference in superoxide dismutase activity (p>0.05). Glutathione peroxidase activity was increased in adrenomedullin treated group but this was statistically insignificant (p>0.05). All enzyme activities were decreased by cold stress (p<0.05). In Adrenomedullin+cold stress group, only the glutathione peroxidase activity was significantly decreased (p<0.05). Conclusion: It is concluded that cold stress induces decrease in catalase, superoxide dismutase and glutathione peroxidase activities in rat liver. Adrenomedullin treatment corrected only glutathione peroxidase activity while decreasing catalase and superoxide dismutase activities further. The discrepancy may be explained by different responses of antioxidant systems to oxidative stress. It can be concluded that oxidative factors may display unexpected effects on the regulation of glutathione peroxidase activities in the adrenonmedullin case.