Testosterone enhancement of thyroid carcinoma in rats: the role of TSH

Journal Article · Mon Dec 01 00:00:00 EST 1986 · Surgery; (United States)

OSTI ID:6776107

Hofmann, C; Oslapas, R; Nayyar, R; McCall, A; Paloyan, E

Radiation treatment of Long-Evans male rats (40 mu Ci Na131I at the age of 2 months) led to a high incidence of thyroid follicular carcinomas at the age of 24 months; castration of males before irradiation caused a significant reduction in incidence of this tumor. In this study, replacement testosterone (T) was administered to castrated male rats by means of implanted, slow-release hormone-containing pellets (T-physiologic dose). Three testosterone doses (0.1T, 1.0T, and 30T) were used to treat groups of castrated irradiated and castrated nonirradiated rats from 2 to 18 months of age. The incidence of thyroid follicular carcinoma at 18 months in irradiated rats depended on the dose of replacement testosterone used. Tumor incidence was 8%, 14%, 41%, and 50% after treatment with 0T, 0.1T, 1.0T, and 30T, respectively. The incidence of thyroid follicular carcinoma in nonirradiated rats ranged from 0 to 7%. Mean serum thyroid-stimulating hormone (TSH) values in irradiated animal groups were elevated significantly above those for age-matched nonirradiated animals. The degree of TSH elevation in irradiated animals was related directly to the testosterone-replacement level. All rat groups showed age-dependent decreases in serum T4 levels, and T4 levels were also lowered by replacement testosterone in nonirradiated castrated animals. In aging irradiated animals, serum T4 levels were similarly decreased by testosterone, despite elevated TSH levels in these groups. In this study, testosterone appeared to act indirectly to promote development of irradiation-induced thyroid tumors by early and prolonged elevation of TSH levels.

• Research Organization: VA Hospital Hines, IL
• OSTI ID: 6776107
• Journal Information: Surgery; (United States), Vol. 6
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CARCINOMAS
RADIOINDUCTION
TESTOSTERONE
RESPONSE MODIFYING FACTORS
THYROID
BIOLOGICAL RADIATION EFFECTS
RATS
THYROXINE
TSH
TUMOR PROMOTERS
AMINO ACIDS
ANDROGENS
ANDROSTANES
ANIMALS
BIOLOGICAL EFFECTS
BODY
CARBOXYLIC ACIDS
DISEASES
ENDOCRINE GLANDS
GLANDS
HORMONES
HYDROXY COMPOUNDS
KETONES
MAMMALS
NEOPLASMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY HORMONES
PROMOTERS
RADIATION EFFECTS
RODENTS
STEROID HORMONES
STEROIDS
THYROID HORMONES
VERTEBRATES
560152* - Radiation Effects on Animals- Animals