Further improvements in the hepatocyte primary culture DNA repair test for carcinogens: detection of carcinogenic biphenyl derivatives.

DNA repair in hepatocyte primary cultures was induced by simultaneous treatment with the carcinogen and [3H] thymidine for 18 h beginning immediately after attachment of cells. The unscheduled DNA synthesis elicited by carcinogens was determined by counting grains with an automatic grain counter. In 5 biphenyl derivatives, a correlation was found between carcinogenicity and the ability to induce DNA repair. Hence, the method offers promise as a means of screening chemical carcinogens.