Pancreatic nitric oxide and oxygen free radicals in the early stages of streptozotocin-induced diabetes mellitus in the rat
Braz. j. med. biol. res
;
33(11): 1335-42, Nov. 2000. graf
Article
in English
| LILACS
| ID: lil-273215
RESUMO
The objective of the present study was to explore the regulatory mechanisms of free radicals during streptozotocin (STZ)-induced pancreatic damage, which may involve nitric oxide (NO) production as a modulator of cellular oxidative stress. Removal of oxygen species by incubating pancreatic tissues in the presence of polyethylene glycol-conjugated superoxide dismutase (PEG-SOD) (1 U/ml) produced a decrease in nitrite levels (42 percent) and NO synthase (NOS) activity (50 percent) in diabetic but not in control samples. When NO production was blocked by N G-monomethyl-L-arginine (L-NMMA) (600 ÁM), SOD activity increased (15.21 +/- 1.23 vs 24.40 +/- 2.01 U/mg dry weight). The increase was abolished when the NO donor, spermine nonoate, was added to the incubating medium (13.2 +/- 1.32). Lipid peroxidation was lower in diabetic tissues when PEG-SOD was added (0.40 +/- 0.02 vs 0.20 +/- 0.03 nmol/mg protein), and when L-NMMA blocked NOS activity in the incubating medium (0.28 +/- 0.05); spermine nonoate (100 ÁM) abolished the decrease in lipoperoxide level (0.70 +/- 0.02). We conclude that removal of oxygen species produces a decrease in pancreatic NO and NOS levels in STZ-treated rats. Moreover, inhibition of NOS activity produces an increase in SOD activity and a decrease in lipoperoxidation in diabetic pancreatic tissues. Oxidative stress and NO pathway are related and seem to modulate each other in acute STZ-induced diabetic pancreas in the rat
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Pancreas
/
Oxidative Stress
/
Nitric Oxide Synthase
/
Diabetes Mellitus, Experimental
/
Nitric Oxide
Language:
English
Journal:
Braz. j. med. biol. res
Journal subject:
Biology
/
Medicine
Year:
2000
Type:
Article
Affiliation country:
Argentina
/
Spain
Institution/Affiliation country:
Consejo Nacional de Investigaciones Científicas y Técnicas/AR
/
Consejo Nacional de Investigaciones Científicas y Ténicas/AR
/
Instituto de Investigaciones Biomedicas de Barcelona/ES
Similar
MEDLINE
...
LILACS
LIS