Spontaneous and radiation-induced benign tumors in parabiont rats. [X radiation]
Spontaneous benign tumors are present in nearly half of NEDH rats. A single whole-body exposure of 1000 R X radiation delivered to a rat supported by a shielded parabiont partner induced high incidence rates of benign tumors in several radioresponsive organs: ovary, 49.7%; adrenal medulla (males, 23.9%; females, 15.2%); mammary tissue (females, 19.6%); islands of Langerhans (males, 15.3%); and liver (cholangiomas) (males, 7.4%; females, 13.8%). Both hormonal imbalance and radiation effects appear to be involved. Parabiosis decreased the incidence of pheochromocytoma, but irradiation of a partner increased it. Mammary tumors occurred on the average 200 days earlier in irradiated rats than in their unirradiated controls. Benign tumors rarely affected health. The incidence was not increased in most organs following irradiation. Three control series were used: single rats, control parabiont rats and the shielded partners of the irradiated partners. Although endometrial polyps were more frequent in irradiated than in shielded partners, they probably resulted from hormonal imbalance. Adenomas of the pituitary were most frequent in shielded female parabiont partners (16.0%). Their incidence was decreased by radiation to 4.2%. Most types of benign tumors rarely progress to malignancy.
- Research Organization:
- New England Deaconess Hospital, Boston
- OSTI ID:
- 6670102
- Journal Information:
- Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 75:1; ISSN RAREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BODY
DISEASES
ELECTROMAGNETIC RADIATION
GLANDS
HORMONES
IONIZING RADIATIONS
MAMMALS
MAMMARY GLANDS
MOSAICISM
NEOPLASMS
ORGANS
PARABIOSIS
RADIATION EFFECTS
RADIATIONS
RADIOINDUCTION
RATS
RODENTS
VERTEBRATES
X RADIATION