Active oxygen species in the liver of rats submitted to chronic hypobaric hypoxia.
The spontaneous in situ liver chemiluminescence of female rats submitted to 4,400 m (simulated altitude) for 2 mo and of their corresponding controls at sea level was determined as an approach to the measurement of the intracellular steady-state concentrations of singlet oxygen and oxygen free radicals. Spontaneous liver chemiluminescence was decreased by approximately 40% in hypoxic rats, whereas CCl4-induced chemiluminescence was unchanged. Liver mitochondria isolated from hypoxic rats showed a 53% decreased rate of H2O2 production and an increased content of cytochrome b (36%), with normal content of cytochromes c1, c, and a-a3. Superoxide dismutase showed a 26% decrease in activity, whereas catalase and glutathione peroxidase activities were not significantly decreased by this extent of hypoxia. Cytochrome P-450 and glutathione contents were unchanged. There were no significant differences in the hydroperoxide-initiated chemiluminescence (an estimation of tissue chain-breaker antioxidants) of homogenates, mitochondria, and microsomes. Results suggest that in chronic hypoxia there is a lower rate of generation of active oxygen species in liver, leading to a decreased steady-state concentration of singlet oxygen.
Costa
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LE
Instituto de Investigaciones Cardiológicas, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
Llesuy
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S
Boveris
A
A
D000531:Altitude; D000818:Animals; D002251:Carbon Tetrachloride / Q000494:pharmacology; D002908:Chronic Disease; D005260:Female; D006706:Homeostasis; D006861:Hydrogen Peroxide / Q000378:metabolism; D000860:Hypoxia / Q000209:etiology / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008163:Luminescent Measurements; D008929:Mitochondria, Heart / Q000378:metabolism; D008930:Mitochondria, Liver / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*
D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D002251:Carbon Tetrachloride