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Free keywords:
Animal; Body Weight; In Vitro; Liver Neoplasms; Neoplasms, Experimental; Nitrosamines; Nucleosides; Rats; RNA; RNA, Neoplasm; Tritium
Abstract:
The incorporation of 3H-cytidine (RNA synthesis) into liver explants under standardized in vitro conditions was measured during hepatocarcinogenesis by continuous oral administration of diethylnitrosamine (DENA) to adult rats. At the daily dose of 5 mg DENA per kg body weight, the median time until death with hepatocellular carcinomata was 160 days ±6%. (S.D.) in the control group; the tumour yield was 100%. 3H-cytidine incorporation, measured at 2-4 day intervals, showed an initial depression followed by a slow increase, and finally surpassed the control level after about 140 days of carcinogenesis. The results are discussed in relation to findings by other groups, especially with respect to possibly different effects, on RNA synthesis of the two related liver carcinogens DENA and N-nitroso-morpholine.
