||7,12-Dimethylbenz(a)anthracene-DNA Adducts in Sprague-Dawley and Long-Evans Female Rats: The Relationship of DNA Adducts to Mammary Cancer.
Daniel, F. B. ;
Joyce, N. J. ;
||Health Effects Research Lab., Cincinnati, OH. ;National Inst. for Occupational Safety and Health, Cincinnati, OH. Div. of Biomedical and Behavioral Science.
Breast carcinoma ;
Deoxyribonucleic acid ;
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7,12-dimethylbenz(a)anthracene (DMBA) is a powerful carcinogen to the mammary gland of the pubescent female Sprague-Dawley (S.D.) rat but is a much less potent inducer of mammary adenocarcinoma in the female Long-Evans (L.E.) rat of the same age. The livers of both strains are refractory to DMBA. The maximum levels of DMBA-DNA adducts formed, in both the mammary gland and liver following intraperitoneal (i.p.) administration of (3H)DMBA (21 micromoles) were significantly higher (p < 0.01) in the resistant, L.E. strain than the sensitive S.D. strain. Maximal levels of DMBA-DNA adducts were observed at 48 hr post administration of the hydrocarbon for both organs of both strains. For the S.D. animals no significant loss of adducts (relative to the 48 hr maxima) was observed from either organ at the last time point (336 hr). In contrast both organs of the L.E. strain showed some evidence of adduct removal.