Quantitative exposure of grafted rat tracheas to 7,12-dimethylbenz(a)anthracene

Journal Article · Sun May 01 00:00:00 EDT 1977 · Cancer Res.; (United States)

OSTI ID:7289166

Griesemer, R A; Nettesheim, P; Martin, D H; Caton, Jr, J E

A method was developed for continuously exposing tracheal epithelium to measured amounts of carcinogen. Beeswax was the vehicle for sustained release of carcinogen, and tracheas transplanted to s.c. sites were target tissues. In the experiment reported here, transplanted rat tracheas were exposed to a potent carcinogen, 7, 12-dimethylbenz(a)anthracene (DMBA). The rate of release of DMBA from the beeswax carrier within the tracheal lumen approached first order when the initial concentration of carcinogen was high (3200 to 325 ..mu..g in a 24.45-mg pellet). With lower concentrations, where the carcinogen was dissolved in the beeswax, initial release was rapid, and most of the carcinogen was delivered within 4 weeks. At high DMBA dose levels, the entire tracheal epithelium was uniformly replaced by keratinizing squamous metaplasia after 1 week of exposure, and after 2 months, when from 280 to 910 ..mu..g DMBA had been delivered, all transplants had developed invasive squamous carcinomas. Sarcomas also developed in 19% of the transplants. At lower dose levels the epithelial reactions were more varied, and tumor development was more protracted. The lowest DMBA dose presently known to induce carcinomas in this experimental model is 40 ..mu..g, which is in the dose range used for tumor initiation in skin carcinogenesis studies in mice.

• Research Organization: Oak Ridge National Lab., TN
• OSTI ID: 7289166
• Journal Information: Cancer Res.; (United States), Vol. 37
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BENZANTHRACENE
BIOLOGICAL EFFECTS
NEOPLASMS
TRACHEA
CARCINOGENS
EPITHELIUM
RATS
ANIMALS
AROMATICS
BODY
CONDENSED AROMATICS
DISEASES
HYDROCARBONS
MAMMALS
ORGANIC COMPOUNDS
RESPIRATORY SYSTEM
RODENTS
TISSUES
VERTEBRATES
560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)