Biological effects of the superoxide radical.

Oxidative stress: from basic research to clinical application.

As a normal attribute of aerobic life, structural damage to organic compounds of a wide variety (DNA, proteins, carbohydrates and lipids) may occur as a consequence of oxidative reactions. Oxidative damage inflicted by reactive oxygen species has been called “oxidative stress”. Biological systems contain powerful enzymatic and nonenzymatic antioxidant systems, and oxidative stress denotes a shift in the prooxidant/antioxidant balance in favor of the former. Diverse biological processes such as inflammation, carcinogenesis, ageing, radiation damage and photobiological effects appear to involve reactive oxygen species. This field of research provides new perspectives in biochemical pharmacology, toxicology, radiation biochemistry as well as pathophysiology.

Biochemistry of Oxidative Stress

The Isoenzymes of Glutathione Transferase

Purification from pig liver of a protein which protects liposomes and biomembranes from peroxidative degradation and exhibits glutathione peroxidase activity on phosphatidylcholine hydroperoxides.

Rat hepatic cytosolic glutathione-dependent enzyme protection against lipid peroxidation in the NADPH-microsomal lipid peroxidation system.

Liver and lung activities of the antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were determined in control and copper-deficient rats. Decreased activity of SOD was found in liver and decreased activity of the selenoenzyme GSH-Px was found in liver and lung in the copper-deficient animals. The decreased liver activity of GSH-Px could be partially corrected by daily supplementation of the basal diet with sodium selenite. Urinary, fecal and biliary excretion of 75SeO3(2-) were determined in controls and copper-deficient rats in order to assess selenium losses. Urinary excretion of 75Se was not different in the two groups. Fecal loss of 75Se was increased in the copper-deficient animals when compared to controls and biliary excretion was decreased. Tissue retention of 75Se was also determined in both groups. Retention of 75Se in the copper-deficient rats was increased in brain and lung and decreased in liver. This pattern of tissue retention of 75Se is similar to that which occurs in selenium-deficient rats. Copper deficiency in rats results in decreased liver activity of both the copper-containing enzyme SOD and the selenoenzyme GSH-Px. The mechanism of decreased GSH-Px activity is unknown.

Effects of Copper Deficiency on the Activity of the Selenoenzyme Glutathione Peroxidase and on Excretion and Tissue Retention of 75SeO32

Enhanced Pulmonary Toxicity in Copper-Deficient Rats Exposed to Hyperoxia

Non-selenium-dependent glutathione peroxidase activity in rat lung: association with lung glutathione S-transferase activity and the effects of hyperoxia.

Effect of selenium deficiency on liver and blood glutathione peroxidase activity in guinea pigs.

Richard A. Lawrence

Papers

Rat hepatic cytosolic glutathione-dependent enzyme protection against lipid peroxidation in the NADPH-microsomal lipid peroxidation system.

Effects of Copper Deficiency on the Activity of the Selenoenzyme Glutathione Peroxidase and on Excretion and Tissue Retention of 75SeO32

Enhanced Pulmonary Toxicity in Copper-Deficient Rats Exposed to Hyperoxia

Non-selenium-dependent glutathione peroxidase activity in rat lung: association with lung glutathione S-transferase activity and the effects of hyperoxia.

Effect of selenium deficiency on liver and blood glutathione peroxidase activity in guinea pigs.