Metabolic activation by hamster and rat hepatocytes in the Salmonella mutagenicity assay

Intact and homogenized hepatocytes from untreated or Aroclor 1254-treated male and female noninbred Sprague-Dawley rats and noninbred Syrian golden hamsters were compared for their ability to metabolize chemicals in the Salmonella-mammalian microsome mutagenesis assay. The following chemicals were used: two aromatic amines, 2-amino-anthracene and N-2-fluorenylacetamide; two polycyclic aromatic hydrocarbons, 3-methylcholanthrene and benzo[a]pyrene (BP); and one nitrosamine, diethylnitrosamine (DENA). With one exception, hepatocytes from hamsters were more active than were hepatocytes from rats in the activation of these mutagens. The homogenized preparations from Aroclor 1254-treated rats were slightly more active with BP than was the equivalent hamster preparation. Intact hepatocytes from Aroclor 1254-treated hamsters were more efficient at metabolizing the aromatic amines and DENA, whereas homogenates were more effective with the hydrocarbons. Results were similar with the rat preparations, except that only large quantities of Aroclor 1254-treated intact male rat hepatocytes appeared to activate DENA. These results suggest that, in the choice of an activation system, the kind of chemical being evaluated should be considered.