• Preventive Nutrition and Food Science
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• v.5 no.2
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• pp.105-108
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• 2000

To evaluate an effect of oxygen free radical on the toluence metabolism, the rats were fed on a tungstate sup-plemented diet(0.75g of tungstate included in 1kg of standard diet) or a standard diet. To the present xanthine oxidase deficient animal model, toluene(0.15ml/100g of body weight) was injected and then the animals were sacrificed after 24 hrs to determine the toluene metabolizing enzyme activities and toluene metabolite, hippuric acid concentration. The increasing rate of urinary hippuric acid concentration was significantly(p<0.01) higher in tungstate fed animals than in standard diet fed ones. Hepatic cytochrome P_450 contents were significantly higher(p<0.01) in tungstate fed animals than in standard diet fed ones. And tungstate fed animals showed a ten-dency of higher activities of benzylalcohol dehydrogenase while a significantly higher activites of benzaldehyde dehydrogenase (p<0.01) than standard diet fed animals. In conclusion, the more possibly reduced oxygen free radical in toluene-treated rats fed with a tungstate supplemented diet than in those fed with a standard diet would be responsible for the enhancement of toluene metabolism.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.6
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• pp.678-684
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• 1993

To evaluate the role of xanthine oxidase in liver damage by CCl4, a group of rats were fed tungstate for a month, which suppressed the activities of xanthine oxidase in serum and liver. Control group of rats were fed standard diet without tungstate. Liver damage was induced both in tungstate fed and control groups by two intraperitoneal injections of CCl4 at the level of 0.1ml/100g body weight at intervals of 24 hours. Increases in the levels of serum alanine aminotransferase by CCl4 were significantly smaller in tungstate fed rats than in control rats. Concomitantly, histopathologic changes were less in tungstate fed rats than in control ones. In rats either treated with CCl4 or not, hepatic type O xanthine oxidase activities were remarkably reduced by tungstate feeding. Hepatic aniline hydroxylase activities were higher in rats fed tungstate than control rats when animals were not treated with CCl4, but the enzyme activities were lower in tungstate fed rats than control when they were treated with CCl4. Neither tungstate feeding nor CCl4 treatment caused any significant changes in hepatic glutathione contents, and activities of hepatic glutathione S-transferase, glutathione peroxidase and superoxide dismutase. It is concluded xanthine oxidase reaction augment CCl4 induced liver damage via oxygen free radical system.

• Biomedical Science Letters
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• v.9 no.2
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• pp.75-84
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• 2003

To evaluate the influence of hepatic oxygen free radical systems on liver injury by topical p-phenylenediamine (PPD) application on rat skin, PPD (25 mg/16.5 $\textrm{cm}^2$) was topically applied to the abdominal region 5 times every other day and sacrificed. By PPD treatment, increasing rate of liver weight/body weight (%), serum activities of alanine aminotransferase and aspartate aminotransferase and decreasing rate of microsomal glucose-6-phosphatase activity were higher in the rats fed tungstate supplemented diet than those fed a standard diet. These findings indicate that group fed tungstate supplemented diet have more severe liver injury compared with group fed standard diet on topical PPD application. However, the activities of oxygen free radical generating enzymes such as xanthine oxidase (XO) and cytochrome P450 dependent aniline hydroxylase and those of oxygen free radical scavenging enzymes were not found to be different between these two animal groups. In the present study, a novel monitoring method to detect the generating of oxygen free radicals in liver extract was devised. Throughout this method, the oxidized PPD produced by oxygen free radicals was determined colorimetrically. The increasing rate of PPD oxidation by liver homogenate was higher in tungstate fed animals than in standard diet fed ones. Among the fractionations of liver extract, the mitochondrial and postmitochondrial fractions in the liver extract of tungstate fed animals led to a higher availability of PPD oxidation by PPD treatment compared with standard diet fed ones. In conclusion, these results suggest that an enhanced liver injury in tungstate fed animals treated with PPD may be due to oxygen free radicals produced in other systems except oxygen free radicals generating from cytosolic XO system. Especially, oxidative availability by PPD can be used for oxygen free radical detection in some tissue.