Prepubertal exposure to a pharmacological dose (500 mg kg-1) of the phyto-oestrogen genistein can reduce the incidence and multiplicity of carcinogen-induced mammary tumours in rats.
However, such an exposure also disrupts the function of the hypothalamic-pituitary-gonadal axis, making it unsuitable for breast cancer prevention.
We studied whether prepubertal exposure to genistein at a total body dose broadly comparable to the level typical of Oriental countries, approximately 1 mg kg-1 body weight, affects mammary tumorigenesis.
We also studied whether prepubertal exposure to zearalenone, a major source for phyto-oestrogens in the USA, influences breast cancer risk.
Prepubertal rats were treated between postnatal days 7 and 20, with 20 mug (-1 mg kg-1 body weight) of either genistein or zearalenone.
Zearalenone exposure significantly reduced both the incidence and multiplicity of mammary tumours induced by 7,12-dimethyibenz (a) anthracene (DMBA).
Genistein exposure significantly reduced tumour multiplicity, but not tumour incidence, when compared with vehicle-treated animals.
Furthermore, 60% of the tumours in the genistein group were not malignant, while all the tumours analysed for histopathology in the vehicle and zearalenone groups were adenocarcinomas.
A higher number of differentiated alveolar buds, and lower number of terminal ducts, were present in the DMBA-treated mammary glands of the phyto-oestrogen exposed rats. (...)
Mots-clés Pascal : Adénocarcinome, Glande mammaire, Facteur risque, Oestrogène, Phytohormone, Exposition, Zéaralénone, Tumorigénicité, Epidémiologie, Modèle animal, Rat, Rodentia, Mammalia, Vertebrata, Animal, Tumeur maligne, Glande mammaire pathologie, Hormone stéroïde sexuelle, Hormone ovarienne
Mots-clés Pascal anglais : Adenocarcinoma, Mammary gland, Risk factor, Estrogen, Phytohormone, Exposure, Zearalenone, Tumorigenicity, Epidemiology, Animal model, Rat, Rodentia, Mammalia, Vertebrata, Animal, Malignant tumor, Mammary gland diseases, Sex steroid hormone, Ovarian hormone
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 99-0406441
Code Inist : 002B04D12. Création : 22/03/2000.