Use of unscheduled DNA synthesis in freshly isolated human intestinal mucosal cells for carcinogen detection.

Mucosal cells freshly isolated from human intestine with pronase retain the capacity to undergo DNA repair synthesis (unscheduled DNA synthesis) during a 2-hr exposure to the carcinogen, N-methyl-N'-nitro-N-nitrosoguanidine, and the procarcinogen, aflatoxin B1. This procedure combining the use of human intestinal mucosal cells and the measurement of unscheduled DNA synthesis may provide a highly relevant and convenient test system for the detection of cell-specific, direct-acting, and activation-dependent chemical carcinogens. The use of whole-cell preparations in such in vitro studies may be of additional significance in view of growing evidence for artefactual metabolism by subcellular fractions.