Genotoxicity of 2-Amino-1-methyl-6-phenylimidazo [4, 5-b] pyridine (PhIP) in Drosophila melanogaster and Enhancement of DNA Damaging Activity by Pretreatment with β-Naphthoflavone and Ethanol

The genotoxicity of 2-amino-1-methyl-6-phenylimidazo [4, 5-b] pyridine (PhIP) was assayed by the wing spot test for detecting somatic cell mutations and the DNA-repair test for detecting DNA damage with Drosophila melanogaster. Although PhIP increased the frequency of small single spots in a dose-dependent manner in the wing spot test, no large single spots and twin spots were induced to a significant extent. In the DNA-repair test PhIP showed clear DNA-damaging activity. The DNA-damaging potency of PhIP was significantly increased when larvae were pretreated with β-naphthoflavone (BNF) 24-48 h after oviposition. Excessive reduction of the Rec- male/Rec+ female ratio was also observed in ethanol-pretreated stock compared with stock not pretreated. These results indicate that alcohol and BNF, both enzyme inducers, enhance the in vivo DNA-damaging activity of PhIP.