ABSTRACT
AIM To study the cancer promoting effects of N nitrosodiethylamine (DEN) and 2 Acetylaminofluorene (2 AAF). METHODS Medium Term Rat Liver Bioassay (MTRLB). Male SD rats were initially given a single dose (200 mg?kg -1 ) of DEN ip and starting 2 weeks later, were treated with 10, 33 and 100 ppm DEN in drinking water, or with 2 2, 6 6 and 22 mg?kg -1 2 AAF by gavage for 6 weeks. All rats were subjected to two thirds partial hepatectomy at week 3 and killed at the end of week 8. Carcinogenic potential was scored by comparing the numbers and areas in induced glutathione S transferase placental form (GST P) positive foci in the liver with those of corresponding control group given DEN alone. RESULTS Both DEN and 2 AAF caused the increases of the numbers and areas of GST P positive foci in the liver, and showed dose response relationship. CONCLUSION Both DEN and 2 AAF shows cancer promoting effects, and MTRLB was a convenient, economical and effective tool to study the cancer promoting effects of test chemicals.