抄録
Four groups of 7-week-old male Donryu rats, 120 heads in total, were fed with 0.05% of 3'-methyl-4-dimethylaminoazobenzene for 3, 4, 5, and 6 months. Appearance of tumor rats, autopsy findings, and histological studies of the induced liver cancers were made in each case and compared among the 4 groups. On the other hand, primary tumor ascites, and the largest and the second largest tumor nodules were transplanted intraperitoneally to normal Donryu rats and their transplantability was studied and compared with each other. In addition, successive transplantation was attempted and the transplantability and median survival time in days were examined in each case. Throughout these experiments, two apparent facts were observed. One was that the transplantability of the induced liver cancer has a close relation to the amount of the carcinogen given and it was demonstrated that the longer the period of feeding was, the higher the transplantability of the induced liver cancer was. The second was that the transplantability of the largest tumor was 2-3 times higher than that of the second largest. Based on these results, the mechanism of carcinogenesis was discussed.
