The mutagenicity of chemically synthesized metabolites of 16,17-dihydro-15H-cyclopenta[a]phenanthrene and its carcinogenic 11-methyl homologue.

Putative synthetic metabolites of the hydrocarbon 16,17-dihydro-15H-cyclopenta[a]phenanthrene and its carcinogenic 11-methyl analogue, namely trans-3,4-dihydroxy-3,4,16,17-tetrahydro-15H- cyclopenta[a]phenanthrene and its 11-methyl derivative, together with the four associated trans-3,4-dihydroxy-syn- and anti-1,2-epoxides, were assayed for mutagenicity in the Ames test with Salmonella typhimurium TA100 with and without microsomal activation. The hydrocarbons were weakly mutagenic and the 3,4-diols were more strongly so, but all required activation to express their mutagenic potential. All four diol-epoxides were much more potent mutagens, even in the absence of activation. This is in accord with the anticipated metabolic activation sequence: hydrocarbons-->3,4-diols-->3,4-diol-1,2-epoxides.