Prolactin and aging: X-irradiated and estrogen-induced rat mammary tumorigenesis

Journal Article · Sun Jul 01 04:00:00 EDT 1984 · J. Natl. Cancer Inst.; (United States)

OSTI ID:6130909

Ito, A; Naito, M; Watanabe, H; Yokoro, K

Both sexes of inbred WF rats at either 8 or 28-60 weeks of age were exposed to 200 rad whole-body radiation, 2.5 or 5.0 mg 17 beta-estradiol (E2), or both agents The female rats treated with E2 alone or with both X-rays and E2 at 8 weeks of age showed a high incidence of mammary carcinomas (MCA), a large increase in pituitary weight, and a rise in serum prolactin (PRL) levels. However, the same treatments to males did not induce MCA despite a moderate increase in both pituitary weight and serum PRL. Ovariectomy prior to E2 treatment failed to modify the occurrence of MCA or pituitary tumors. When X-rays and E2 were given to female rats at 28-60 weeks of age, pituitary weight, serum PRL levels, and the incidence of MCA were unaffected. When the E2 pellet was kept for the first 24 weeks and withdrawn during the last 12 weeks, the incidence of MCA, pituitary weight, and serum PRL was low. It was concluded that: 1) the pituitary glands of young female rats were susceptible to E2 treatment but were insensitive in older females, and 2) the occurrence of MCA in female rats appeared to be promoted by elevated PRL levels secreted by E2-induced pituitary tumors. Mammary tissue of male rats was less sensitive to PRL levels in the development of MCA.

• Research Organization: Univ. of Hiroshima, Japan
• OSTI ID: 6130909
• Journal Information: J. Natl. Cancer Inst.; (United States), Journal Name: J. Natl. Cancer Inst.; (United States) Vol. 73:1; ISSN JNCIA
• Country of Publication: United States
• Language: English

Related Subjects

560152* -- Radiation Effects on Animals-- Animals
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AGE DEPENDENCE
ANIMALS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BODY
CARCINOMAS
DISEASE INCIDENCE
DISEASES
ELECTROMAGNETIC RADIATION
ENDOCRINE GLANDS
ESTRADIOL
ESTRANES
ESTROGENS
EXTERNAL IRRADIATION
FEMALES
GLANDS
GONADOTROPINS
HORMONES
HYDROXY COMPOUNDS
IONIZING RADIATIONS
IRRADIATION
KINETICS
LTH
MAMMALS
MAMMARY GLANDS
NEOPLASMS
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY GLAND
PITUITARY HORMONES
RADIATIONS
RADIOINDUCTION
RADIOSENSITIVITY EFFECTS
RATS
REACTION KINETICS
RODENTS
SENSITIVITY
SEX DEPENDENCE
STEROID HORMONES
STEROIDS
VERTEBRATES
WHOLE-BODY IRRADIATION
X RADIATION