title: Rat mammary deoxyribonucleic acid synthesis during the estrous cycle, pregnancy, and lactation in relation to mammary tumorigenesis: its implication for human breast cancer.
abstract: Rat mammary DNA synthesis is greatly reduced during late pregnancy and lactation; this corresponds to the decreased incidence of induced mammary tumors by chemical carcinogens during these periods. The protective effects of pregnancy and lactation against mammary tumorigenesis of rats and human subjects may be explained by the prolonged phases of mitotic rest encountered during pregnancy and lactation.
mesh_terms: D000818:Animals; D001943:Breast Neoplasms; D004247:DNA / Q000096:biosynthesis*; D004971:Estrus; D005260:Female; D007774:Lactation; D011247:Pregnancy; D011270:Pregnancy, Animal; D051381:Rats; D013997:Time Factors
chemical_list: D004247:DNA