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- MakaleYalnız künye2010Scopus SJRQ3THE ROLE OF METHYLATED ADRENOMEDULLIN IN ENZYMATIC ANTIOXIDANT DEFENSE RESPONSE TO COLD STRESS
Yildirim, Nuran Cikcikoglu; Yurekli, Muhittin
The aim of our study was to investigate the effects of methylated adrenomedullin (met-AdM) on some antioxidant enzymes, such as catalase (CAT), glutathione peroxidase (GSH-P-X) and superoxide dismutase (SOD) in rat kidney and heart tissues after cold stress treatment. Male Wistar rats were divided into 4 groups (control, met-AdM, cold stress and cold stress + met-AdM treatments). The rats were kept at room temperature, exposed to a 16/8-hours light/dark cycle. The rats were maintained at ad libitum (free) feeding habit. In met-AdM treated group, animals received intraperitoneal injection of met-AdM (2 mg/g body weight) once a day during a week. For the cold stress exposure, the rats were kept in separate cages at 10 degrees C for a week. Control group rats were kept at laboratory conditions. CAT, GSH-P-X and SOD enzyme activities were investigated in kidney and heart tissues. In kidney tissue compared to control, CAT and GSH-P-X enzyme activity was decreased but SOD was increased in met-AdM-treated group. In met-AdM+cold stress group, only the SOD enzyme activity was significantly increased but CAT and GSH-P-X decreased. SOD and GSH-P-X enzyme activities were increased by cold stress but CAT was decreased in kidney. In heart tissue, CAT and GSH-P-X activities were decreased but SOD was increased in met-AdM-treated group compared to control. All enzyme activities were decreased in met-AdM+cold stress group as well as by cold stress in heart, with regard to control. Cold stress can disrupt the balance in an oxidant/antioxidant system and cause oxidative damage to kidney and heart tissues by altering the enzymatic and non-enzymatic antioxidant status. We can suggest that met-AdM has possible roles in regulation of stress but we need further studies revealing responses of met-AdM in different tissues.
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İncele - MakaleYalnız künye2010Scopus SJRQ3Investigation of Some Antioxidant Enzymes Activities Depending on Adrenomedullin Treatment and Cold Stress in Rat Liver Tissue
Yildirim, Nuran Cikcikoglu; Yürekli, Muhittin; Yildirim, Numan
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.
AtıfWoS8İncele - MakaleYalnız künye2010Scopus SJRQ4Stress-Induced Changes in Tyrosine Hyroxylase Enzyme Activity and Adrenomedullin Levels in Rat Hypothalamus, Adrenal Medulla and Heart Tissues
Yildirim, Nuran Cikcikoglu; Yurekli, Muhittin
In this study, it was aimed to investigate the effects of chronic cold stress on adrenomedullin levels and tyrosine hydroxylase enzyme activities in some rat tissues. In this study, 12 female Sprague Dawley rats weighing 200 to 250 g were used. Rats were housed under diurnal lighting conditions (12-12 h) with free access to food and water. For this study, rats were divided into two groups, namely control group and cold stress treated group. Adrenomedullin levels were measured by high performance liquid chromatography. Tyrosine hydroxylase enzyme activities was spectrometrically measured. Tyrosine hydroxylase activity was found to be increased significantly (p<0.05) in adrenal medulla, hypothalamus and heart tissues depending on cold stress treatment. Adrenomedullin levels were determined to be decreased in the cold stress treatment group. The differences of between control and cold stress treatment groups were significant (p<0.05). The results suggested that adrenomedullin may play a possible role in adaptation to stress. Exposure to cold increases the synthesis and release of catecholamines. Tyrosine hydroxylase is the rate limiting step in the biosynthesis of catecholamines for this reason cold stress increased tyrosine hyroxylase enzyme activities. Further studies are needed to reveal correlation between adrenomedullin, tyrosine hydroxylase and cold stress.
AtıfWoS6İncele - MakaleYayıncıda açık erişim2010Scopus SJRQ4Adrenomedullin administration alters vascular endothelial growth factor levels in rats in cold stress
Yildirim, Nuran Cikcikoglu; Yurekli, Muhittin
Background: Many endogenous peptides play important regulatory roles in angiogenesis by modulating endothelial cell behavior. Adrenomedullin (AdM) is one of such factors. Angiogenesis and vascular endothelial growth factor (VEGF) are indistinguishable. Exposure to cold environment stimulates capillary angiogenesis. Objectives: Examine the effect of the bioactive peptide AdM on VEGF levels in rat liver, lung, brain, and heart tissues after cold stress treatment. Methods: Male wistar rats were divided into four groups as control, AdM treatment, cold stress and AdM+cold stress treated groups. In AdM-treated group, animals received intraperitoneal injection of AdM (2000 ng/kg body weight) once a day during a week. For the cold stress exposure, the rats were kept in separate cages at 10 degrees C for a week. Results: The administration of AdM increased VEGF levels in all tissues in cold exposed rats. Conclusion: AdM may be a major regulatory factor in angiogenesis by modulating VEGF levels that is closely associated with cold exposure-related metabolic stimulation.
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