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

Abstract

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 When the E2 pellet was kept for the first 24 weeks and withdrawn during the last 12 weeks, the incidence of MCA, pituitary weight, and serum PRL was low.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 elevatedmore » PRL levels secreted by E2-induced pituitary tumors. Mammary tissue of male rats was less sensitive to PRL levels in the development of MCA.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Univ. of Hiroshima, Japan
OSTI Identifier:
6130909
Resource Type:
Journal Article
Journal Name:
J. Natl. Cancer Inst.; (United States)
Additional Journal Information:
Journal Volume: 73:1
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; CARCINOMAS; RADIOINDUCTION; ESTRADIOL; BIOLOGICAL EFFECTS; RADIOSENSITIVITY EFFECTS; LTH; BIOCHEMICAL REACTION KINETICS; MAMMARY GLANDS; AGE DEPENDENCE; DISEASE INCIDENCE; FEMALES; PITUITARY GLAND; RATS; SENSITIVITY; SEX DEPENDENCE; WHOLE-BODY IRRADIATION; X RADIATION; ANIMALS; BODY; DISEASES; ELECTROMAGNETIC RADIATION; ENDOCRINE GLANDS; ESTRANES; ESTROGENS; EXTERNAL IRRADIATION; GLANDS; GONADOTROPINS; HORMONES; HYDROXY COMPOUNDS; IONIZING RADIATIONS; IRRADIATION; KINETICS; MAMMALS; NEOPLASMS; ORGANIC COMPOUNDS; ORGANS; PEPTIDE HORMONES; PITUITARY HORMONES; RADIATIONS; REACTION KINETICS; RODENTS; STEROID HORMONES; STEROIDS; VERTEBRATES; 560152* - Radiation Effects on Animals- Animals

Citation Formats

Ito, A, Naito, M, Watanabe, H, and Yokoro, K. Prolactin and aging: X-irradiated and estrogen-induced rat mammary tumorigenesis. United States: N. p., 1984. Web.
Ito, A, Naito, M, Watanabe, H, & Yokoro, K. Prolactin and aging: X-irradiated and estrogen-induced rat mammary tumorigenesis. United States.
Ito, A, Naito, M, Watanabe, H, and Yokoro, K. 1984. "Prolactin and aging: X-irradiated and estrogen-induced rat mammary tumorigenesis". United States.
@article{osti_6130909,
title = {Prolactin and aging: X-irradiated and estrogen-induced rat mammary tumorigenesis},
author = {Ito, A and Naito, M and Watanabe, H and Yokoro, K},
abstractNote = {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.},
doi = {},
url = {https://www.osti.gov/biblio/6130909}, journal = {J. Natl. Cancer Inst.; (United States)},
number = ,
volume = 73:1,
place = {United States},
year = {Sun Jul 01 00:00:00 EDT 1984},
month = {Sun Jul 01 00:00:00 EDT 1984}
}