Search results for "OXIDASE"
showing 10 items of 927 documents
Hypothalamic reactive oxygen species are required for insulin-induced food intake inhibition: an NADPH oxidase-dependent mechanism
2009
1939-327X (Electronic) Journal Article Research Support, Non-U.S. Gov't; OBJECTIVE: Insulin plays an important role in the hypothalamic control of energy balance, especially by reducing food intake. Emerging data point to a pivotal role of reactive oxygen species (ROS) in energy homeostasis regulation, but their involvement in the anorexigenic effect of insulin is unknown. Furthermore, ROS signal derived from NADPH oxidase activation is required for physiological insulin effects in peripheral cells. In this study, we investigated the involvement of hypothalamic ROS and NADPH oxidase in the feeding behavior regulation by insulin. RESEARCH DESIGN AND METHODS: We first measured hypothalamic RO…
Time course of asymmetric dimethylarginine (ADMA) and oxidative stress in fructose-hypertensive rats: A model related to metabolic syndrome
2011
Asymmetric dimethylarginine (ADMA) is an endogenous modulator of endothelial function and oxidative stress, and increased levels of this molecule have been reported in some metabolic disorders and cardiovascular diseases. The aim of this work was to analyze the time course of dimethylarginine compounds and oxidative stress levels and the relationship between these and cardiovascular function in fructose-hypertensive rats.90 male Sprague-Dawley rats were randomized into 2 groups, fed for 3 months with standard (C) chow supplemented or not with fructose (F, 60%). After sacrifice at different weeks (W), the aorta and plasma were harvested to assess the vascular and biochemical parameters. Our …
Antioxidant effect of Ajuga iva aqueous extract in streptozotocin-induced diabetic rats.
2009
The purpose of this study was to investigate the possible antioxidant effect of an aqueous extract of Ajuga iva (Ai) in streptozotocin (STZ)-induced diabetic rats. Twelve diabetic rats were divided into two groups fed a casein diet supplemented or not with Ai (0.5%), for 4 weeks. In vitro, the Ai extract possessed a very high antioxidant effect (1 mg/ml was similar to those of trolox 300 mmol/l). The results indicated that plasma thiobarbituric acid reactive substances (TBARS) values were reduced by 41% in Ai-treated compared with untreated diabetic rats. TBARS concentrations were lower 1.5-fold in liver, 1.8-fold in heart, 1.9-fold in muscle and 2.1-fold in brain in Ai-treated than untreat…
Experimental diabetic neuropathy: role of oxidative stress and mechanisms involved.
1998
Oxidative stress has been related to the development of diabetic neuropathy. Experimental diabetes (alloxan injection to mice) promotes early biochemical changes in peripheral nervous tissue, e.g., decrease in Na,K-ATPase activity and glutathione (GSH) peroxidase (GSHPx) activity. The former decrease can be reverted by inhibiting protein kinase C (PKC), since it has been reported that PKC is activated in these experimental conditions. Here we present data demonstrating that the inhibition of PKC, as early as 4 days after alloxan administration, is not able to return to normal values GSHPx activity in sciatic nerve of diabetic mice. Thus, it would fit with our previous proposal of the possib…
Decreased glutathione peroxidase activity in sciatic nerve of alloxan-induced diabetic mice and its correlation with blood glucose levels.
1993
The effect of alloxan-induced diabetes on glutathione peroxidase (GSH-Px) activity in sciatic nerve of mice has been studied. We have found, 7 days after alloxan treatment, a significant decrease in this enzymatic activity in the cytosol of sciatic nerve of diabetic mice, and moreover, that these changes remained unaltered up to 21 days after alloxan injection. No modification in the glutathione content of sciatic nerve of diabetic mice was observed throughout the experiment when compared with controls. The decrease in GSH-Px activity in this tissue shows a good correlation with the increase of blood glucose levels throughout the experiment. It is hypothesized whether a combination of mecha…
Fructose-enriched diet modifies antioxidant status and lipid metabolism in spontaneously hypertensive rats
2005
Abstract Objective High-fructose consumption in industrial countries has been shown to induce metabolic abnormalities or syndrome X. Changes in antioxidant defense are unknown in hypertension associated with metabolic disorders induced by high-fructose feeding. Methods Twenty spontaneously hypertensive rats were assigned to one of two groups; one received a fructose-enriched diet (60% fructose) and the other a starch diet. After a 13-wk diet period, total antioxidant status was assessed in the blood and liver by monitoring the rate of free radical-induced red blood cell hemolysis. Antioxidants (enzymes and vitamins) were determined in blood and liver. Gene expression of antioxidant enzymes …
Vascular Dysfunction in Streptozotocin-Induced Experimental Diabetes Strictly Depends on Insulin Deficiency
2010
<i>Objective:</i> In previous studies we and others have shown that streptozotocin (STZ)-induced diabetes in rats is associated with vascular oxidative stress and dysfunction. In the present study, we sought to determine whether vascular dysfunction and oxidative stress strictly depend on insulin deficiency. <i>Methods:</i> The effects of insulin (2.5 U/day s.c., 2 weeks) therapy on vascular disorders in STZ-induced (60 mg/kg i.v., 8 weeks) diabetes mellitus (type I) were studied in Wistar rats. The contribution of NADPH oxidase to overall oxidative stress was investigated by in vivo (30 mg/kg/day s.c., 4 days) and in vitro treatment with apocynin. <i>Results:&…
AT1-receptor blockade by telmisartan upregulates GTP-cyclohydrolase I and protects eNOS in diabetic rats.
2008
Several enzymatic sources of reactive oxygen species (ROS) were described as potential reasons of eNOS uncoupling in diabetes mellitus. In the present study, we investigated the effects of AT1-receptor blockade with chronic telmisartan (25 mg/kg/day, 6.5 weeks) therapy on expression of the BH4-synthesizing enzyme GTP-cyclohydrolase I (GCH-I), eNOS uncoupling, and endothelial dysfunction in streptozotocin (STZ, 60 mg/kg iv, 7 weeks)-induced diabetes mellitus (type I). Telmisartan therapy did not modify blood glucose and body weight. Aortas from diabetic animals had vascular dysfunction as revealed by isometric tension studies (acetylcholine and nitroglycerin potency). Vascular and cardiac RO…
Vascular Dysfunction in Experimental Diabetes Is Improved by Pentaerithrityl Tetranitrate but Not Isosorbide-5-Mononitrate Therapy
2011
OBJECTIVE Diabetes is associated with vascular oxidative stress, activation of NADPH oxidase, and uncoupling of nitric oxide (NO) synthase (endothelial NO synthase [eNOS]). Pentaerithrityl tetranitrate (PETN) is an organic nitrate with potent antioxidant properties via induction of heme oxygenase-1 (HO-1). We tested whether treatment with PETN improves vascular dysfunction in the setting of experimental diabetes. RESEARCH DESIGN AND METHODS After induction of hyperglycemia by streptozotocin (STZ) injection (60 mg/kg i.v.), PETN (15 mg/kg/day p.o.) or isosorbide-5-mononitrate (ISMN; 75 mg/kg/day p.o.) was fed to Wistar rats for 7 weeks. Oxidative stress was assessed by optical methods and o…
Oleanonic acid, a 3-oxotriterpene from Pistacia, inhibits leukotriene synthesis and has anti-inflammatory activity.
2001
One of the best known bioactive triterpenoids is oleanolic acid, a widespread 3-hydroxy-17-carboxy oleanane-type compound. In order to determine whether further oxidation of carbon 3 affects anti-inflammatory activity in mice, different tests were carried out on oleanolic acid and its 3-oxo-analogue oleanonic acid, which was obtained from Pistacia terebinthus galls. The last one showed activity on the ear oedema induced by 12-deoxyphorbol-13-phenylacetate (DPP), the dermatitis induced by multiple applications of 12-O-tetradecanoyl-13-acetate (TPA) and the paw oedemas induced by bradykinin and phospholipase A2. The production of leukotriene B4 from rat peritoneal leukocytes was reduced by ol…