Hepatocarcinogenicity of diethylnitrosamine to the self-fertilizing hermaphroditic fish Rivulus marmoratus (Teleostomi: Cyprinodontidae).

The larvae, 3 days post hatching, of self-fertilizing hermaphroditic fish Rivulus marmoratus were exposed to diethylnitrosamine (DENA) (CAS: 55-18-5; N-nitrosodiethylamine) at levels of 50-400 ppm for 2 hours. At 3-month intervals, the exposed fish were sampled until 9 months postcarcinogen treatment. Hepatomas were induced in 6- and 9- month groups of the 100-ppm-treated and 200-ppm-treated fish. An exposure of fish larvae to 400 ppm DENA also produced similar tumors on 3-, 6-, and 9-month groups. The tumor incidences were clearly dose dependent. These results offered the possibility of the use of R. marmoratus as a suitable model for experimental carcinogenesis.