Lawrence Berkeley National Laboratory

The human colon adenocarcinoma cell line, Caco-2, was used to study intestinal uptake of benzo(a)pyrene (BaP). BaP permeation was measured across Caco-2 monolayers grown on permeable supports that separate two chambers representing the intestinal lumen and the bloodstream. BaP permeation of the cell layer was accompanied by extensive metabolism leading to partial detoxification. In addition there was preferential accumulation of conjugated BaP metabolites in the apical chamber representing the intestinal lumen. We conclude that the intestinal epithelium is an important barrier that limits systemic availability of ingested BaP by presystemic detoxification and reduced uptake over time.