Metabolic activation of 2-aminofluorene, 2-acetylaminofluorene and N-hydroxy-acetylaminofluorene to bacterial mutagens with mussel (Mytilus galloprovincialis) and carp (Cyprinus carpio) subcellular preparations.

1. The mode of activation of 2-aminofluorene (AF), 2-acetylaminofluorene (AAF) and N-hydroxy-acetylaminofluorene (OH-AAF) to Salmonella typhimurium TA 98 mutagens was investigated in subcellular fractions from the digestive gland of the mussel Mytilus galloprovincialis and from the liver of carp Cyprinus carpio. 2. In carp liver microsomes the activation of OH-AAF was due to very active deacetylase, in contrast to undetectable deacetylase-dependent activation in mussel microsomes. 3. AF and AAF are activated in mussel microsomes exclusively by a noninducible FAD-containing monooxygenase, whereas in carp microsomes in addition deacetylase and inducible cytochrome P-450 monooxygenase are involved. 4. N,O-Acetyltransferase, sulfotransferase and paraoxon sensitive cytosolic enzyme (PSCE) are involved in activation of OH-AAF, AF and AAF in both carp and mussel cytosols. 5. The metabolic activation of OH-AAF, AF and AAF to bacterial mutagens found in carp liver is similar to that described in livers of experimental mammalian species and strikingly different from the mode of activation found in mussel digestive gland.