Level of 3-Methylcholanthrene in Mammary Glands of Rats after Intragastric Instillation of Carcinogen.

Abstract

With recent development of spectrophotofluorometers, it has been possible to determine distribution of 3-methylcholanthrene (3 MT) in tissues on a quantitative basis and to carry out detailed clearance studies in specific tissues. 3 MT in a single dose of 10 mg/ml sesame oil when fed to rats through a gastric tube, concentrated in the breast and fat of virgin female rats and in milk and breast of lactating rats. The levels of 3 MT in other tissues were either very small or insignificant. It was further demonstrated that following a single feeding of 3 MT in a dose of 30 mg/ml sesame oil, the carcinogenic hydrocarbon decreased rapidly in the breast and fat within 72 hr., but a significant amount of it remained in both tissues at the end of 8 days. These results seem to indicate that there are 2 factors in chemical carcino-genesis; 1st concentration of administered carcinogen in the target tissue and 2d, persistence of the carcinogen in these tissues.