LUNG TUMORS IN MICE SUCKLED BY 3-METHYLCHOLANTHRENE-TREATED MOTHERS

Abstract

A potent chemical carcinogen, 3-methylcholanthrene, given to lactating mice, is transferred via the milk to their suckling offspring, which develop lung tumors in their adult ages. The incidence of tumor-bearing animals was about 60% in male and 30% in female offspring, while no tumors developed in mice suckled by untreated mothers. The carcinogen in the milk and tissues was measured radiometrically to confirm its transfer via milk to the suckling mice. The amount of carcinogen in the lungs of the sucklings was less than 13.5ng/mg of wet tissue when 5mg was given to lactating mothers by stomach tube. This agrees well with the data obtained previously in fetal lungs when mother animals near term were treated with the carcinogen in the same manner. By means of gas chromatography-mass spectrometry, ethanol-soluble fractions of milk from the stomachs of sackling mice were analyzed and the parent carcinogen, its 2-hydroxy, dehydro, and 1, 2-dihydroxy derivatives were detected. These chemicals are all carcinogenic in mice and reported to be more potent in this order.