Hepatic RNA synthesis in rats treated with ethylene thiourea.

The ability of ethylene thiourea (ETU) to inhibit RNA synthesis in rat liver was investigated. This compound, a possibly carcinogenic metabolite to the ethylene-bis-dithiocarbamate fungicides, was administered to rats by intraperitoneal injection, by nasogastric tube and in the diet, and rates of RNA synthesis were determined. By contrast with the carcinogens thioacetamide and acetylaminofluorene, high doses of ETU administered by any of these routes failed to inhibit the synthesis of nuclear or cytoplasmic RNA. In this respect ETU appears to differ from most hepatocarcinogens in its effect on cellular metabolism.