Bisphenol A (BPA, 4,4'-isopropylidenediphenol), an endocrine disrupter with estrogenic properties, was supplied to tobacco BY-2 cells in suspension culture and the chemical nature of its metabolites was investigated. The concentration of BPA in the culture medium decreased rapidly and became undetectable at 2.5 h after the application. Four metabolites of BPA were observed in a methanol extract of the cells when the culture was supplemented with [(14)C]BPA. The most abundant metabolite was determined to be 4,4'-isopropylidenediphenol-O-beta-D-glucopyranoside (BPAG) by mass spectrometry, nuclear magnetic resonance spectroscopy and by hydrolysis with beta-glucosidase. This identification was confirmed by synthesis. When [(14)C]BPA was administrated to tobacco seedlings from their roots, radioactivity was incorporated in BPAG and three unidentified metabolites. These metabolites were accumulated in the leaves after 4 h exposure, indicating that tobacco seedlings absorbed BPA through their root systems, metabolized to its beta-glucoside and translocated the metabolites to their leaves.