Nicotine and cotinine in breast fluid.

Breast fluid which bathes the mammary ductal epithelium may contain tumorogenic components. In view of the number of tobacco components inhaled during smoking, it was of interest whether nicotine and its metabolites were present in this fluid. Fluid was obtained from the nipple from menstruating women who were smokers and non-smokers. In smokers, nicotine and cotinine were detectable in the fluid 30 min after smoking. Further analysis of breast fluid may give leads as to whether components present are related to breast carcinogenesis.