Life-span studies in rats exposed to 239PuO2 aerosol. II. Nonpulmonary tumor formation in control and exposed groups.
Female young adult, SPF, Wistar rats, obtained from the same supplier over an 18-month period, were examined in a life-span study with inhaled 239PuO2. Nonpulmonary tumors were evaluated both in 1052 rats comprising 16 controls groups and in 2105 exposed rats. Tumors in the pituitary gland, mammary glands, uterus, and thyroid glands, in order of decreasing prevalence, accounted for 90% of all tumors. Uterine tumors comprised 55% of all nonpulmonary malignant tumors. A substantial variability in tumor incidence was seen in most organs and for most tumor types among the 16 cohort subgroups, which was not explained by husbandry conditions or mortality patterns. The incidence of thyroid tumors ranged from 0 to 21% and uterine tumors from 14 to 45% among control cohorts. Pulmonary metastases were seen in 12% of all rats irrespective of treatment, two thirds of which were uterine adenocarcinomas that appeared histologically similar to some primary lung adenocarcinomas. A tumor incidence of about 1.5% was associated with metal identification ear tags. Except in the lung, no significant difference was found in tumor location or type between control and exposed rats. A twofold or greater increase in tumors in exposed rats was found in Zymbal gland, bladder, brain, and liver; tumor incidence in each organ was < 1%.
Sanders
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CL
Washington State University, Health Research and Education Center, Richland 99352.
D000230:Adenocarcinoma / Q000209:etiology / Q000556:secondary; D000336:Aerosols; D000818:Animals; D005260:Female; D008136:Longevity / Q000187:drug effects; D008175:Lung Neoplasms / Q000556:secondary*; D008325:Mammary Neoplasms, Experimental / Q000209:etiology; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D010911:Pituitary Neoplasms / Q000209:etiology; D011005:Plutonium / Q000008:administration & dosage / Q000009:adverse effects*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012878:Skin Neoplasms / Q000209:etiology; D013964:Thyroid Neoplasms / Q000209:etiology; D014594:Uterine Neoplasms / Q000209:etiology
D000336:Aerosols; C026885:plutonium dioxide; D011005:Plutonium