著者

Shinichiro Ikezaki Mizuho Takagi Kazutoshi Tamura

出版者

日本毒性病理学会

雑誌

Journal of Toxicologic Pathology (ISSN:09149198)

巻号頁・発行日

vol.24, no.1, pp.37-40, 2011 (Released:2011-04-17)

参考文献数

8

被引用文献数

8 32

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It is important for the assessment of toxicological effects of chemicals to know what kinds of neoplasms naturally occur in the early life of experimental animals. In the present study, we demonstrated spontaneous neoplasms in Sprague-Dawley rats used in 4-, 13- and 26-week toxicity studies conducted at Bozo Research Center in the last decade. The tumors, which were first observed in 19-week-old animals, included anterior adenoma of the pituitary, follicular cell adenocarcinoma and C cell adenoma of the thyroids, nephroblastoma of the kidneys, basal cell tumor of the skin and malignant lymphoma. Thereafter, hemangiosarcoma of the tongue, adenocarcinoma of the submandibular glands, histiocytic sarcoma of the spleen, oligodendroglioma of the brain and adenocarcinoma and fibroadenoma of the mammary glands were detected in 32-week-old animals. The incidences of mammary adenocarcinoma and pituitary anterior adenoma were higher than those of other tumors. The present results showed that the same tumors as reported in aged rats could also develop in younger rats.