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Sequential effects of chemically different carcinogens, dimethylnitrosamine and 4‐dimethylaminoazobenezene, on hepatocarcinogenesis in rats
Author(s) -
Takayama Shozo,
Imaizumi Tadayoshi
Publication year - 1969
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910040402
Subject(s) - carcinogen , medicine , n nitrosodimethylamine , nitrosamine , physiology , gastroenterology , endocrinology , pathology , chemistry , biochemistry
Induction of liver tumors was studied in rats given carcinogens as follows: (1) N‐nitrosodimethylamine (DMN) alone; (2) 4‐dimethylaminoazobenzene (DAB) alone; (3) DMN followed by DAB; and (4) DAB followed by DMN. The main findings were: (1) DAB feeding for 0.62 to 2.5 months, followed by DMN feeding for 5 months, induced liver carcinomas more frequently than did DMN alone given for 5 to 10 months, or DAB alone given for 2.5 months. (2) Likewise, DMN feeding for 0.62 or 1.25 months, followed by DAB feeding for 5 months, induced liver carcinomas more frequently than did DMN alone given for 5 to 10 months or DAB alone given for 2.5 months. Interestingly, when DMN was given for a longer time (2.5 months), followed by DAB for 5 months, 50% of the induced liver tumors were non‐epithelial. (3) Liver tumors were induced by sequential administration of the two carcinogens in doses that did not induce tumors when each carcinogen was given alone over a comparable time period. (4) The latent period for liver tumor development was shorter in groups that received the two carcinogens sequentially than in those that received DAB or DMN alone for comparable time periods.