Yazar "Akbulut, K. Gonca" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • Küçük Resim Yok
    Yayın
    Age-related changes in the rat brain mitochondrial antioxidative enzyme ratios: Modulation by melatonin
    (PERGAMON-ELSEVIER SCIENCE LTD, 2012) Ozturk, Guler; Akbulut, K. Gonca; Guney, Sevin; Acuna-Castroviejo, Dario
    Oxidative stress is an important factor for aging. The antioxidative enzymes glutathione peroxidase (GPx), glutathione reductase (GRd) and superoxide dismutase (SOD) play a crucial role protecting the organism against the age-dependent oxidative stress. Glutathione (GSH) is present in nearly all living cells. GSH is one of the main antioxidants in the cell and it serves several physiological functions. Our purpose was to evaluate the age-related changes in mitochondrial GPx, GRd and SOD activities, and mitochondrial GSH pool in the brains of young (3 months) and aged rats (24 months). We also investigated whether melatonin administration influences these brain mitochondrial enzyme activities and GSH levels in young and aged rats. The results showed that GPx activity increased with age, whereas melatonin treatment decreased GPx activity in the aged rats at levels similar to those in young and young + melatonin groups. The activities of GRd and SOD, however, did not change with age. But, melatonin treatment increased SOD activity in the aged rats. GSH levels, which also increased with age, were not modified by melatonin treatment. The reduction in the SOD/GPx and GR/GPx ratios with age was prevented by melatonin administration. Together, our results suggest that the age-related oxidative stress in rat brain mitochondria is more apparent when the antioxidant enzyme ratios are analyzed instead of their absolute values. The antioxidative effects of melatonin were also supported by the recovery of the enzyme ratios during aging. (C) 2012 Elsevier Inc. All rights reserved.
  • Küçük Resim Yok
    Yayın
    Age-related changes in tissue and plasma zinc levels: Modulation by exogenously administered melatonin
    (TAYLOR & FRANCIS INC, 2008) Oeztuerk, Gueler; Akbulut, K. Gonca; Afrasyap, Lale
    Melatonin (MEL) is synthesized mainly in the pineal gland and derived from 5-hydroxytryptophan (5-HTP). Zinc (Zn) is one of the most important trace elements in the body. Zn and MEL levels are changed with aging. The aim of this study was to investigate the age-related changes of tissue and plasma Zn levels and effect of MEL administration on these parameters. Male wistar rats received for 3 weeks subcutaneous injection of MEL (10mg/kg). Kidney and pancreas Zn levels in old rats were significantly lower than middle-aged group. Spleen, small intestine, and plasma Zn levels were not different in middle-aged and old rats. On the other hand, MEL treatment increased Zn levels of small intestine and plasma in middle-aged rats. However, kidney, spleen, and pancreas Zn levels were unaffected by MEL treatment.
  • Küçük Resim Yok
    Yayın
    Comparison of Melatonin Effect on Oxidant Status and Antioxidant Capacity in Liver and Heart of Young and Aged Rats
    (ELSEVIER TAIWAN, 2013) Guney, Sevin; Cumaoglu, Ahmet; Ozturk, Guler; Akbulut, K. Gonca; Karasu, Cimen
    Background: Oxidative stress is involved in several pathologic conditions such as metabolic or cardiovascular disease, and in aging. Oxidative damage of biomolecules increases with age. Melatonin is the main neurohormone of the pineal gland and specific antioxidants may act against age-related oxidative damage. Objective: This study investigated the effects of administration of melatonin on aging-related parameters such as total oxidant status (TOS), hydrogen peroxide (H2O2) and lipid hydroperoxide (LOOH) levels and total antioxidant capacity (TAC) in the heart and liver in a rat model of aging. Methods: Young (3-month-old) and aged (24-month-old) male Wistar rats were divided into control and melatonin-treated groups. Melatonin was given for 21 days (10 mg/kg/day). At the end of the treatment period, TOS, TAC, H2O2, and LOOH levels were measured. Results: H2O2 in the liver, but not in the heart, was found to be increased in aged rats. Melatonin treatment diminished H2O2 in the heart of both group of rats compared with those of untreated control rats. Melatonin treatment also led to a decrease in H2O2 in the liver of aged rats. LOOH were found to be increased in both tissues of aged rats whereas melatonin treatment decreased LOOH levels in heart and liver tissues of aged rats. In the young rats melatonin also inhibited LOOH in liver. TAC in heart and liver was not found to be statistically different between young and aged rats. In young rats, melatonin treatment resulted in an increase in TAC that was associated with increased H2O2. In the liver and heart of the rats, TOS was increased with age and was ameliorated by melatonin treatment. Conclusion: Our results demonstrate that there is no dramatic overall decline in the antioxidant system with age. However, total oxidant status increased with age. Melatonin has a restorative effect on oxidative status. Copyright (C) 2012, Taiwan Society of Geriatric Emergency & Critical Care Medicine. Published by Elsevier Taiwan LLC. All rights reserved.
  • Küçük Resim Yok
    Yayın
    Histochemical observations on protective effects of melatonin against carbon tetrachloride (CCl4) - induced hepatotoxicity
    (WILEY-BLACKWELL, 2015) Ozerkan, Dilsad; Ozsoy, Nesrin; Akbulut, K. Gonca; Guney, Sevin; Ozturk, Guler
    …