Metabolic activation of 2-aminofluorene in the Salmonella mutagenicity assay by different S-9 preparations.
Before exerting a carcinogenic or mutagenic effect, many chemicals must undergo metabolic activation. The most widely used activation system is the 9,000 g supernatant fraction (S-9) of rat liver homogenate, prepared from male rats pretreated with Aroclor 1254 (AC). The present study compares the capabilities to induce metabolic activation of 2-aminofluorene (2-AF), using different sources of S-9 preparations as a test-promutagen, both in the Ames test and in the minimal saline liquid medium (MSLM). In particular, S-9 preparations of liver and kidney fractions from male rats and guinea pigs, with or without AC or phenobarbital (PB) pretreatment, were used. The 2-AF was tested in Salmonella typhimurium TA 1538 strain (frame-shift mutation) at different level of concentrations. In the Ames test the enzymatic activation of liver fractions, induced by PB, shows a large increase of mutagenicity of 2-AF in both animal species studied. The AC pretreatment in rats significantly reduced the mutagenic activity of 2-AF, when compared with controls. With rat renal microsomes no differences were observed in mutagenicity as compared with controls. A significant increase was seen in the microsomes of guinea pigs pretreated with AC. The experiments carried out with MSLM confirmed the results in full.
D000818:Animals; D001711:Biotransformation; D005449:Fluorenes / Q000378:metabolism* / Q000633:toxicity; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D009152:Mutagenicity Tests; D009153:Mutagens / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012486:Salmonella typhimurium / Q000235:genetics
D005449:Fluorenes; D009153:Mutagens; C012177:2-aminofluorene