• Korean Journal of Veterinary Research
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• v.41 no.4
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• pp.583-589
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• 2001

To estalish bio-indices for detection of the development of multistep hepatotumorigenesis, rats were fed water containing 0.01% diethylnitrosamine (DEN) ad libitum for 13-14 weeks. Hepatocellular carcinoma was developed by treatment with DEN, DEN only was able to induce hepatic tumors in rats without any other cocarcinogen. Compared to control group, liver cytosol protein concentration in all treated grous was significantly decreased (p<0.05). From week to week, $20{\alpha}$-hydroxysteroid dehydrogenase ($20{\alpha}$-HSD) activity was increased and the highest activity was observed on the 12th week (p<0.05). In addition, the urine biopterin concentration was also significantly increased compared to control groups (p<0.05) in a time course manner. These results indicated that $20{\alpha}$-HSD activity, urine biopterin and liver cytosol protein concentration might be very useful maker to hepatic tumorigenesis.

• Korean Journal of Veterinary Service
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• v.22 no.1
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• pp.61-70
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• 1999

This study is concerned with assessment of diethylnitrosamine(DEN) induced liver cell carcinogenesis by measurement of changes preceding the development of neoplasms. Therefore, it was undertaken to investigate the changes of liver-specific enzyme activities in rats (Sprague-Dawley) by ad libitum feeding of DEN. And also, as another objective index in urine, the level of urinary biopterin was measured by high performance liquid chromatography(HPLC) method. The results were as follows ; 1. Minor behavioral change, brittleness of hair and decreased amount of water and diet intake were observed in rats 7 weeks after DEN administration. 2. The body and liver weights were significantly(p<0.05) decreased in rats 11 weeks after DEN administration. 3. The ratio of liver weight to body weight was rather stable and not significantly decreased in the all treatment groups. 4. The liver specific enzyme activities(AST, ALT,$\gamma$-GTP) were significantly(p<0.05) increased in all treatment groups compared to control group. 5. Compared to normal level, urine biopterin level was significantly (p<0.05) increased in all treatment groups(p<0.05). In conclusion, this result confirmed that the DEN was one of the potent hepatocarcinogens. In experimental model of rats exposed to DEN, the results indicated that values of liver specific enzyme activities(AST, ALT, $\gamma$-GTP) and urine biopterin level could be useful complementary tumor indices.

• Korean Journal of Microbiology
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• v.34 no.4
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• pp.243-247
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• 1998

Comparative analyses of intracellular biopterin contents and its biosynthetic enzymes were performed in Allomyces macrogynus. Biopterin content in fresh weight was 14-fold higher in mycelium than in zoospore. Enzyme activities of GTP cyclohydrolase I and 6-pyruvoyltetrahydropterin synthase in ammonium sulfate fractions were approximately 2-fold higher in mycelium. On the other hand, sepiapterin reductase (SR) activity was 10 fold higher in zoospore. Northern blot assay also demonstrated that SR transcript was abundant in zoospore. These results suggest a possible involvement of tetrahydrobiopterin in cellular differentiation of Allomyces macrogyllus as well as provide an experimental basis to elucidate the physiological function of SR in this organism.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.3161-3163
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• 2011

• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.213.2-213
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• 1994

No Abstract, See Full Text