MECHANISM OF INDUCTION OF MAMMARY NEOPLASMS IN RATS BY RADIATION: RELATION TO DOSE AND OVARIAN STATUS
In considering the mechanisms of radiation-induced neoplasia, quantitative dose-effect data, and information on the possible influence of tissues other than the target radiation to Sprague-Dawley rats has been shown to result in a high incidence of mammary gland neoplasms (adenofibromas, fibroadenomas, adenocarcinomas, fibrosarcomas). Neoplasms appeared as early as 2 proximately 60% or more by the 10th month. Tumors in non-irradiated animals were extremely rare in this producing tumors by a factor of 0.8. Dose-dependency studies have shown that the effect is directly proporthat the extrapolated curve passes through zero if the on the mechanisms of induction of tumore have shown incidence. Above 400 r the incidence fell of with increasing dose, related to radiation-induced depressed ovarian function as indicated by estrus studies and by uterine weight at autopsy. Some tumors showed further conditioning in that on transplantation growth was optimal only in animals with ovarian hormone present. sub-transplants. The dose dependency to low value exhitited by the radiation- induced neoplasms in the present experiments can be considered as evidence for duction. The dose dependency of effect obtained, however, was manifest only if the proper hormonal status in the host was maintained. These data are pertinent to the controversial problem of radiation -induced neoplasia, particularly at low dose levels. (auth)
- Research Organization:
- Brookhaven National Lab., Upton, N.Y.; Children's Cancer Research Foundation, Boston
- NSA Number:
- NSA-12-014491
- OSTI ID:
- 4318685
- Report Number(s):
- A/CONF.15/P/885
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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