Dişi ve erkek sıçanların mangan superoksit dismutaz aktivitesi ve ekspreyonu ile mitokondriyal oksidan üretiminde yaşla ilişkili değişiklikler

İstanbul Bilim Üniversitesi, Tıp Fakültesi.Objective: The aim of this study was to examine the age- and gender-related differences in peroxide production, manganese superoxide dismutase (MnSOD) activity and expression in liver mitochondria of Wistar rats at 12 and 24 months of age. Methods: The chemiluminometric method for peroxide production, fluorometric method for malondialdehyde (MDA) levels, cumene hydroperoxide assay for glutathione peroxidase (GPx), the nitroblue tetrazolium assay for MnSOD activity, and Western-blotting for MnSOD expression were used. Results: Mitochondrial peroxides are increased significantly in both genders as aging proceeded, and females exhibited more profound increment than the males. Mitochondrial SOD and GPx activities remained unaltered between 12 and 24 months of age, with no difference between two genders. The gender- and age-related differences were observed in MnSOD expression (p<0.01). The SOD activity per expressed enzyme protein was significantly decreased in 24-month-old animals of both genders (p<0.01). Female rats had a significantly lower ratio than their male counterparts (p<0.05). In females, the expression was not associated with the activity of MnSOD, while a positive correlation existed between these parameters in males (r=0.573, p=0.001). Enzyme expression was found to be significantly higher in female rats as compared to their male counterparts. Liver mitochondria are less prone to oxidative damage in female rats compared to males as observed at 12 and 24 months of age Conclusions: An involvement of factors other than estrogen seems to be relevant for the difference in the MnSOD activity and expression pattern between two genders

A study on the relationship between homocysteine and diabetic nephropathy in rats

Hyperhomocysteinemia is known to be associated with many of the occlusive vascular diseases including ischemic heart disease. Elevated plasma total homocysteine (t-Hcy) is also remarkably common among patients with moderate to severe renal failure. The purpose of this study was to investigate the role of homocysteine (Hcy) in the pathogenesis of diabetic nephropathy in the rat. Additionally, any effect of aminoguanidine (AG), an inhibitor of advanced glycation end product (AGE) formation, on the onset of nephropathic symptoms and on the concentrations of Hey was searched for. Diabetes was induced in male Wistar albino rats (6 months old) by a single injection of 50 mg kg(-1) streptozotocin (STZ) into the penile vein. Animals with blood glucose levels higher than 350 mg dl(-1) 72 It after STZ injection were included in the study. Age-matched rats receiving a single dose of citrate buffer served as controls. One half of the control and diabetic groups received AG via drinking water (1 g l(-1)). The experimental period lasted for ten weeks. Animals were killed by cardiac venipuncture after 24 hour urine samples were collected. Serum t-Hcy was quantified using HPLC, and urinary GAGS using the spectrophotometric 1,9-dimethyl methylene blue dye method. Serum glucose. protein, creatinine and total sulfydryl (t-SH) measurements, and urinary protein determinations were carried out spectrophotometrically. In diabetic rats, serum t-Hcy levels were significantly decreased (P < 0.001), and were negatively correlated with the urinary protein concentration (r = -0.67, P < 0.05). Urinary GAG levels were also increased in diabetic rats (P < 0.001). AG neither affected the t-Hcy levels, nor ameliorated the nephropathic symptoms. These results indicate that diabetic nephropathy is not linked to homocysteinemia in the rat. (C) 2002 Elsevier Science Ltd

Serum asymmetric dimethylarginine and nitric oxide levels in obese postmenopausal women

İstanbul Bilim Üniversitesi, Tıp Fakültesi.BACKGROUND: It has been reported that estrogen deficiency after menopause might cause a decrement in nitric oxide (NO) bioavailability by increasing the level of asymmetric dimethylarginine (ADMA), a major endogenous nitric oxide synthase inhibitor, thus leading to abnormalities in endothelial function. Because NO plays an important role on feeding behavior, ADMA may be involved in the pathogenesis of obesity, too. This cross-sectional study aimed to evaluate the relations of ADMA and NO with the obesity-linked peptides, such as ghrelin, leptin, and adiponectin in postmenopausal women free of hormone replacement therapy. METHODS: Adiponectin, ghrelin, leptin, ADMA, and NO(x) (total nitrite/nitrate) were measured in 22 obese (BMI: 30-47 kg/m(2)) and 19 normal weight (BMI: 21.5-26 kg/m(2)) postmenopausal women.Anthropometric measurements (height, weight, BMI, waist, and hip circumferences) were recorded. Statistics were made by the Mann-Whitney U-test. RESULTS: Ghrelin and adiponectin levels were significantly lower (P<0.001), whereas ADMA and leptin levels were higher in obese women than in normal weight controls (P<0.01 and 0.001, respectively). BMI was correlated negatively with adiponectin and ghrelin and positively with ADMA and leptin levels. No correlation existed between ADMA and NO. CONCLUSION: Estrogen deficiency alone may not cause an increase in ADMA levels unless the women are prone to disturbances in energy homeostasis. In spite of the high ADMA levels, the unaltered NO levels in plasma may be owing to ongoing inflammatory conditions