1988 Fiscal Year Final Research Report Summary
フェノキシ系除草剤の発癌性に関する遺伝毒性学的研究
| Project/Area Number |
62570227
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Hygiene
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| Research Institution | Niigata University School of Medicine |
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Principal Investigator |
YAMAMOTO Masaharu Niigata University of Medecine, Professor, 医学部, 教授 (40018693)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAGI Shuko Niigata University School of Medicine, Assistant, 医学部, 助手 (30134109)
WATANABE Gen-ichi Niigata Institute of Industrial Health, Director emeritus, 健康開発研究所, 所長 (50018280)
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| Project Period (FY) |
1987 – 1988
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| Keywords | phenoxy herbicides / MCPA-E / MCPB-E / MCPA / subacute toxicity / chronic toxicity |
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| Research Abstract |
Epidemiological studies on the biliary tract cancer(btc) have been undertaken in our laqboratory. One reason for that is the death rate for btc in niigata prefecture is the highest in japan. In addition,it is noted that the prefectures with higher death rates clustered in the areas where the rice production was also high. Based on these findings, the role of agricultural chemicals,the dietary pattern and other geographical characteristics in drinking water or soil were investigated. First of all,the role of agricultural chemicals was tested.
Yamamoto ET AL. analysed an ecological correlation between the use of chemicals (1962-1975) and standardized mortality ratios(SMR_s for BTC(1975) in japan and found that the use of MCPA-E and MCPB-E was frequently correlated with SMR_s. Although the presence of ecological correlation does not always mean the causal one, it may be worthwhile to reveal why such kind of statistical association was observed. As a part of investigation into the biochemic
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al characteristics of these compounds, subacute and chronic toxicity is examined in mice.
1)Subacute toxicity study of MCPA-E and MCPB-E
Phenoxy herbicides,MCPA-E and MCPV-E were evaluated for subacute toxicity by gavage in ICR male mice. Groups of 10 mice were given daily doses of MCPA-E(50, 100 and 200 mg/kg b.wt.) and MCPB-E(25, 50 and 100 mg/kg b.wt) 5 days per week for 6 weeks. After the completion of the teratment,histological changes were examined. In addition to the 6-week experiment,MCPA-E or MCPB-E was given for 12 weeks.
The relative liver weight of mice in the group treated with mcpa-e for 6 weeks increased significantly. The remarkable histological change was seen in the liver of mice at all dose levels of mcpa-e and MCPB-E in the 6-and 12-wk experiments. Hepatic cell atypia and central necrosis were the major findings in mice with hepatomegaly. As to the histology of the gallbladder, the specific change was not observed in the mice treated with MCPA-E and MCPB-E.
2)Chronic toxicity study of MCPA
The animals used were ICR male nice, aged 4-5 weeks old. They were given solid feed mixed with MCPA, 0(only corn oil), 40,200,1000 and 5000 ppm, for 1.5 years and bred without the treatment for 1 year. The animals were sacrificed and examined histopathologically,whenecer they were dead or visibly ill during the experiment.
Im MCPA treated animals,the increase of kupffer cells, anisocytosis of hepatocytes and late nodules were frequently observed in comparison of the control animals. As to the pathological changes of the gallbladder, the proliferation of papillary formation was evident in the MCPA-treated animals. The pseudopyloric gland metaplasia was also found in the treated animals, but there was no difference in its occurrence between the treated and the untreated groups. Less
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Research Products
(4 results)
