A comparative study on the protective effects of 17beta-estradiol, biochanin A and bisphenol A on mammary gland differentiation and tumorigenesis in rats.
Mammary tissue differentiation and tumorigenesis were studied in female rats following subcutaneous injection at 2, 4 and 6 days after birth with low or high doses of 17beta-estradiol (0.1 or 10 microg; E2), biochanin A (0.1 or 10 mg; BCA) or bisphenol A (0.1 or 10.0 mg; BPA). Half of the rats were killed on day 35 to analyze the terminal end bud (TEB), terminal duct (TD) and alveolar bud (AB) of the mammary tissue. The remaining rats were injected, ip, with a dose of 50 mg/kg of N-nitroso-N-methylurea (MNU) at 7 weeks of age and sacrificed 26 weeks later. The incidence and multiplicity of mammary tumors (MT) decreased among all three different treated groups, dose-dependently. However, the pattern of mammary gland differentiation varied. No significant difference was observed after E2 administration. TEB decreased dose-dependently in BCA treated groups and the number of TD and AB were suppressed significantly in BPA high dose group.
Yin
Hong
H
Department of Cancer Research, Research Institute for Radiation Biology and Medicine, Hiroshima University. Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan.
Ito
Akihiro
A
Bhattacharjee
Dilip
D
Hoshi
Masaharu
M
D000818:Animals; D000831:Animals, Newborn; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D001559:Benzhydryl Compounds; D001835:Body Weight / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D019833:Genistein / Q000494:pharmacology*; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000254:growth & development / Q000473:pathology; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D008770:Methylnitrosourea; D009929:Organ Size / Q000187:drug effects; D010636:Phenols / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000098826:Bisphenol A Compounds
D016588:Anticarcinogenic Agents; D001559:Benzhydryl Compounds; D004958:Estradiol; D019833:Genistein; D008770:Methylnitrosourea; D010636:Phenols; C006780:bisphenol A; D000098826:Bisphenol A Compounds; C004541:biochanin A