• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.932-938
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• 1999

The present study was designed to determine long-term feeding effects of vitamin E and BHT (butylated hydroxytoluene) on serum biochemical profiles, organ weight, and intestinal and hepatic antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and glutathione-S-transferase (GST) in ICR mice. Four wk old ICR mice (n=8 per group) were fed the diets supplemented with vitamin E (I ; 0.03% and II ; 0.3%) and BHT (I ; 0.05% and II ; 0.5%) for 12 months. Feeding the diets containing vitamin E and BHT had no effects on growth and serum biochemical profiles. However, feeding the diets supplemented with 0.5% BHT for 12 months significantly increased liver weight of the mice. In the small intestine, there were no effects of vitamin E or BHT on SOD and GSH-PX activities in the mucosa. However, the activity of intestinal GST of the mice that received 0.5% BHT was almost twice as high as that of control mice. In the liver, the activity of SOD was not affected by feeding antioxidants for 12 months, whereas GSH-PX activity was significantly increased in mice that received the diets containing BHT (0.05%, 0.5%) and vitamin E (0.03%, 0.3%). In addition, supplementation of 0.5% BHT markedly enhanced hepatic GST activity compared with other groups. Enhanced activity of GSH-PX in response to feeding vitamin E or BHT might aid hepatic enzymes to eliminate active oxygen in organs from mice. However, we could not exclude the possibility of increased lipid peroxidation by high dosage of BHT supplementation. More detailed study is necessary for assessment of preventive or toxicological effects of high dosage of BHT supplementation.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.185.3-186
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• 2003

It is well-known that bisphenol A(BPA), an industrial raw material for polycarbonate and epoxy resins, shows estrogenic activity. Recent research from our laboratory has shown that SPA disrupts interaction between thyroid hormone and its receptor in a non-competitive manner, and alters the thyroid-hormone dependent expression of growth hormone(GH) and prolactin(PRL). (omitted)

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.05a
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• pp.95.2-95
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• 2003

Ketoconazole is a well-studied drug that blocks fungal growth and testosterone synthesis in humans and rodents by inhibiting the activity of cytochrome P-450 enzymes. But there were no reports that ketoconazole affects on enzymes related to degradation of testosterone. Aromatase converts testosterone to estradiol. Change of aromatase protein level may destroy hormone homeostasis. (omitted)

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.173.1-173.1
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• 2003

The present study was conducted to determine the effects of bis-carboxyethyl germanium sesquioxide(Ge-132) and caffeic acid phenethyl ester(CAPE) on immune system in female BALB/c mice. The mice were orally exposed continuously to Ge-132 (0, 50, 100, or 200mg/kg), or CAPE (0, 5. 10, or 20mg/kg) for 14 days. Immunomodulatory activity was evaluated by assessment of body and organ weight, lymphocytes blastogenesis, (omitted)

• YAKHAK HOEJI
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• v.42 no.3
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• pp.336-344
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• 1998

Effects of ochratoxin A (OTA) on embryo development were studied in cultured whole embryos from 9.5 day gestation rat for 48 h. OTA (more than $0.5{\mu}g/ml$) induced microcephaly in the cultured rat whole embryos. Protein and DNA content, and DNA synthesis were significantly inhibited by OTA. We next examined whether the microcephaly seen in cultured whole embryo partially results from inhibition of differentiation of embryonic midbrain cells. Embryonic midbrain cells were extracted from 12 day gestation rat embryos, and cultured for 96 hr. OTA ibhibited cell differentiation about 50% over control. We also tested whether OTA-induced embryotoxicity would be associated with oxidative damages. We measured the ${\gamma}$-glutamyltranspeptidase (${\gamma}$-GT) and glutathione peroxidase (GPX) activities, and glutathione (GSH) content in both cultured whole embryos and embryonic midbrain cells. OTA decreased GSH content, whereas slightly increased ${\gamma}$-GT activity, but GPX activity was not significantly changed. These results show that OTA caused the microcephaly and its effect may be partially due to the inhibition of cell differentiation of embryonic midbrain cells, but the role of oxidative damages is not clear in embryotoxicity.

• Environmental Mutagens and Carcinogens
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• v.25 no.1
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• pp.1-5
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• 2005

The present work was undertaken to evaluate the antimetastatic potential of capsaicin (8­methyl-N-vanillyl-6-nonenamide) by measuring its effects on matrix metalloproteinase activity, cell invasion and lung metastasis. Significant inhibition of matrix metalloproteinase-2 activity by capsaicin (100 $\mu$M) was detected by gelatin zymography. In vitro invasion assay showed capsaicin (50, 100 $\mu$M) reduced tumor cell invasion ($28-40\%$). Capsaicin (i.p., 2.5 mg/kg) inhibited development of lung colonization ($58\%$). These results suggest that capsaicin prevents metastasis in part through suppression of invasion of B16F10 melanoma cells by inhibiting matrix metalloproteinase-2 responsible for degradation of extracellular matrix.

• Environmental Mutagens and Carcinogens
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• v.25 no.2
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• pp.66-70
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• 2005

Telomerase, a specialized RNA-directed DNA polymerase that extends telomeres of eukaryotic chromosomes, has activity in most malignant tumors and provides a mechanism for the unlimited potential for division of neoplastic cells. Although telomerase is known to be a regulated enzyme, the factors and mechanisms involved in telomerase regulation are not well understood. In the present study, we compared the effect of 12-O­tetradecanoyl-phorbol-13-acetate (TPA) and non-phorbol ester tumor promoters such as okadaic acid, anthralin and benzoyl peroxide on the expression of telomerase in the mouse skin carcinogenesis system, a well characterized model for studying pre-malignant and malignant progression. We found that most early papillomas harvested after 10 weeks of TPA promotion showed telomerase activity. Other papillomas harvested after 10 weeks of okadaic acid, anthralin and benzoyl peroxide promotion and after single treatment of DMBA only also showed telomerase activity, respectively. On the other hand, normal and all skins surrounded by papillomas harvested after 10 weeks of these promoters has no telomerase activity. Taken together these results, there appears to be no clear association between the level of telomerase activity and protein phosphorylation in mouse skin papillomas and telomerase may be useful as bio-markers in early detection of tumors.

• Environmental Mutagens and Carcinogens
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• v.20 no.1
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• pp.21-25
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• 2000

Recently there is increasing interest in the use of structure activity relationships for predicting the biological activity of chemicals. The reasons for the interest include the decrease cost and time per chemical as compared with animal or cell system for identifying toxicological effects of chemicals and the reduction in the use of animals for toxicological testing. This study is to test the validity of the mutagenicity data generated from QSAR (Quantitative Structure Activity Relationship) program. Thirty chemicals, which had been evaluated by Ames test during 1997-1999, were assessed with TOPKAT QSAR mutagenicity prediction module. Among 30chemicals experimented, 28 were negative and 2 were positive for Ames test. On the contrary, 23 chemicals showed the high confidence level indicating high prediction rate in mutagenicity evaluation, and 7 chemicals showed the lsow to moderate confidence level indicating low prediction in mutagenicity evaluation. Overall mutagenicity prediction rate was 77% (23/30). The prediction rates for non-mutagenic chemicals were 79% (22/28) and mutagenic chemicals were 50% (1/2). QSAR could be a useful tool in providing toxicological data for newly introduced chemicals or in furnishing data for MSDS or in determining the dose in toxicity testing for chemicals with no known toxicological data.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.11b
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• pp.143-143
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• 2002

Capsaicin (8-methyl-N-vanillyl-6-nonenamide), a pungent ingredient of hot chili peppers, has been reported to possess substantial anticarcinogenic and antimutagenic activities. In our previous study, we found that capsaicin (100 ${\mu}$M) induced significant inhibition of matrix metalloproteinase-2 activity by gelatin zymography, and that capsaicin (i.p., 2.5mg/kg) inhibited development of lung colonization (58%) in experimental lung metastasis assay.(omitted)

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.11b
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• pp.162-162
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• 2002

There has been many findings of natural, environmental or manufactered nonsteroidal substances shown to have estrogenic activity. Since estrogens affect reproduction and cellular development to cause disease in people or animals, chronic exposure may have a major impact on health.(omitted)