the hepatocarcinogenic nitrosamines ( n-nitrosodimethylamine , ndma ; n-nitrosodiethylamine , ndea ; n-nitrosomorpholine , nm and n-nitrosodibutylamine , ndba ) were activated to mutagens by s9 and by hepatocytes both derived from noninduced rat livers , ndma and nm inducing more his+ revertants in the presence of hepatocytes .
C0028197
nitrosamines
C0012200
ndea