NO modulates the molecular basis of rat interscapular brown adipose tissue thermogenesis

Molecular mechanisms underlying interscapular brown adipose tissue (IBAT) thermogenesis were elucidated. Namely, gene and/or protein expression of uncoupling protein 1 (UCP1), peroxisome proliferator-activated receptor gamma (PPARgamma), PPARgamma-coactivator-1alpha (PGC-1alpha), vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen (PCNA) - key molecules that regulate thermogenesis-related processes - mitochondriogenesis, angiogenesis and IBAT hyperplasia, in rats subjected to cold (4+/-1 degrees C) for 1, 3, 7, 12, 21 and 45days were investigated. Particularly, to examine influence of nitric oxide (NO) on IBAT thermogenic-program, cold-exposed animals were treated by l-arginine or N(omega)-nitro-l-arginine-methyl ester (L-NAME). Related to control (22+/-1 degrees C), cold induced time-coordinated UCP1, PPARgamma and PGC-1alpha transcriptional activation accompanied by PCNA activation and increased VEGF immunolabeling that correlate with endothelial NO synthase (eNOS) transcriptional activation suggesting NO involvement in these thermogenic-factors activation. Observed molecular changes were translated into increased mitochondrial-remodeling, angiogenesis, and IBAT hyperplasia. l-Arginine augmented and prolonged cold-induced increase of eNOS, inducible NOS and thermogenic-molecules expression, IBAT nerve supply, vascularity, hyperplasia and mitochondrial-remodeling, while L-NAME had an opposite effects. Results show that NO improves thermogenesis-related mitochondriogenesis, angiogenesis and tissue hyperplasia, positively affecting molecular basis of these processes, suggesting that NO is an essential regulator of IBAT thermogenic-program operating, at genes, proteins and tissue structure levels.

Interrelationship of antioxidative status, lipid peroxidation, and lipid profile in insulin-dependent and non-insulin-dependent diabetic patients

This study aimed to investigate the interrelationship of plasma lipid profile, lipid peroxidation, and erythrocyte antioxidative defense in patients with insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetes mellitus. Plasma levels of total cholesterol, triglycerides, and lipid peroxides and the activities of copper, zinc superoxide dismutase (CuZnSOD), catalase, glutathione peroxidase (GSH-Px), as well as the amount of glutathione in erythrocytes, were determined in IDDM, NIDDM, and nondiabetic control subjects. Additionally, morphology of erythrocytes in all subjects was examined. Plasma levels of total cholesterol and triglycerides were significantly increased in NIDDM compared with controls. Also, the lipid peroxide level was higher in NIDDM than in either control or IDDM subjects. CuZnSOD activity in erythrocytes was elevated in NIDDM patients compared with the control. In NIDDM patients, more extensive erythrocyte spherocytosis and echinocytosis compared with both control and IDDM subjects were observed. In contrast with the IDDM group, the observed abnormality in lipid metabolism in NIDDM patients is closely associated with increased lipid peroxidation, changes in antioxidative defense, and erythrocyte morphology.

The effects of cold acclimation and nitric oxide on antioxidative enzymes in rat pancreas

Alterations of pancreatic antioxidative defense (AD) and possible nitric oxide (NO) role in AD organization of adult rats receiving l-arginine.HCl (2.25%) or N(omega)-nitro-l-arginine methyl ester (L-NAME.HCl, 0.01%) as drinking liquids and maintained at room (22+/-1 degrees C) or low (4+/-1 degrees C) temperature for 45 days were studied. For that purpose, copper, zinc- and manganese superoxide dismutase (CuZnSOD, MnSOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione S-transferase (GST) and glutathione reductase (GR) activities were determined. Cold-induced decrease of CuZnSOD was inhibited with L-NAME, while l-arginine produced the same effect as cold in both supplemented groups. Cold acclimation elevated GSH-Px activity. l-Arginine and L-NAME expressed no effect on GSH-Px in rats kept at room temperature. L-NAME additionally elevated cold-induced GSH-Px activity, l-arginine expressing a similar trend. Cold-induced increase in GST activity was inhibited by L-NAME, while l-arginine inhibited this enzyme in both supplemented groups. Cold acclimation increased GR activity in control and L-NAME-treated group and l-arginine expressed a similar trend. Neither of the treatments affected MnSOD and CAT activities. Cold-induced changes of pancreatic AD were additionally affected by the alterations in l-arginine-NO-producing pathway. Some AD changes in the same direction with l-arginine or L-NAME point to the complexity of nitrogen compounds metabolism and function, accompanied by tissue-specific response.

Free radical equilibrium in interscapular brown adipose tissue: relationship between metabolic profile and antioxidative defense

Interscapular brown adipose tissue (IBAT) hyperplasia involves a new metabolic and structural profile, resulting from acclimation of animals to a cold environment. Cold-induced changes of several antioxidative defense (AD) components in IBAT and their interrelationship with uncoupling protein 1 (UCP1), sympathetic innervation and apoptosis were studied using cold-acclimated adult rat males (4 +/- 1 degrees C, 45 days). Their age-matches were maintained at 22 +/- 1 degrees C serving as the controls. In cold-adapted rats, activities of CuZn- and Mn-superoxide dismutase (SOD) and apoptosis were reduced, while catalase (CAT), glutathione peroxidase (GSH-Px), glutathione S-transferase (GST) activities and glutathione (GSH) content were increased compared to the control. IBAT mass, protein content, plasma free fatty acid (FFA) concentration, sympathetic innervation and UCP1 level were significantly increased in cold-acclimated group compared to the corresponding control. These results suggest that decreased CuZn and MnSOD activities in IBAT represent an adaptive response due to UCP1-induced mitochondrial uncoupling. Additionally, intensive fatty acid oxidation led to an increased H(2)O(2) production which resulted in increased CAT, GSH-Px and GST activities and GSH level. Generally speaking, cold-induced changes of AD in the IBAT are closely connected with newly established metabolic profile in this tissue, thus making an important part of the entire tissue homeostasis including cell survival.