Open AccessInfluence of Strain and Sex on the Local Development of Mammary Tumors Induced by Direct Application of DMBA Powder to Rat Mammary Glands
Author(s) -
Tsubura Airo,
Izuno Yoshio,
Shoji Tetsuji,
Kusunose Naotaka,
Morii Sotokichi
Publication year - 1990
Publication title -
acta patholigica japonica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 74
ISSN - 0001-6632
DOI - 10.1111/j.1440-1827.1990.tb01523.x
Subject(s) - dmba , ovariectomized rat , carcinogen , medicine , endocrinology , mammary tumor , mammary gland , 7,12 dimethylbenz[a]anthracene , carcinogenesis , biology , estrogen , cancer , breast cancer , genetics
In order to determine the influence of strain and sex on local carcinogenesis in rat mammary tissue, 1 mg of 7, 12 dimethylbenz(a)anthracene (DMBA) was dusted directly onto the exposed mammary gland of 30‐day‐old Long‐Evans (L‐E) rats and Sprague‐Dawley (S‐D) rats. The experiment was terminated 28 weeks after application of the carcinogen. Tumors measuring between 1 and 2 cm in diameter were harvested from female L‐E rats with high frequency (85%) and long latency (mean: 23.7 weeks after DMBA dusting), and from female S‐D rats with extremely high frequency (98%) and short latency (16.7 weeks). Male rats of both strains were almost identically much less susceptible to DMBA (L‐E; 55%, 25.0 weeks, S‐D; 53%, 23.9 weeks). Ovariectomized S‐D (47%, 24.9 weeks) and orchiectomized S‐D (30%, 24.8 weeks) rats, which were gonadectomized at 30 days of age, respectively, were also much less susceptible. A variety of histologies, mostly malignant epithelial, mesenchymal or mixed tumors, were noted in each group. The carcinomatous response in the mammary tissue was much higher in female S‐D (96%) than in female L‐E (50%) rats, and very low in male and gonadectomized rats (10‐20%). In contrast, the sar‐comatous response in the mammary tissue was moderate in female and male L‐E and male S‐D (43‐50%) rats, and low in the other groups (15‐29%). Acta Pathol Jpn 40: 9–13, 1990.