Light-dependent activation of 7,12-dimethylbenz[a]anthracene to a potent genotoxicant.
7,12-Dimethylbenz[a]anthracene (DMBA), which is widely used in mutagenesis and experimental carcinogenesis, is activated to a mutagen by white fluorescent light. A 40 min exposure to white fluorescent light of Salmonella typhimurium TA98 plates treated with DMBA, in the absence of exogenous metabolism, resulted in an approximately 30-fold increase in the number of histidine revertants. This phenomenon also occurs, with lesser intensity, with other promutagens, such as benzo[a]pyrene or 2-acetylaminofluorene, and in other Salmonella tester strains. Moreover, white fluorescent light is able to activate DMBA to a toxicant for Chinese hamster V79 cells in culture, resulting in very low cell survival. Under these conditions, white fluorescent light-activated DMBA was shown to cause chromosomal aberrations, but not gene mutations, as determined by resistance to thioguanine. This white fluorescent light-dependent activation of DMBA seems to be related to the formation of reactive species, as the addition of vitamin E results in a reduction in the number of histidine revertants induced by white fluorescent light in S. typhimurium TA98.
Cinelli
S
S
Department of Genetic and Cellular Toxicology, Research Toxicology Centre SpA, Pomezia (Roma), Italy.
Falezza
A
A
Ciliutti
P
P
Mariani
M F
MF
Vericat
J A
JA
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000493:pharmacokinetics* / Q000528:radiation effects* / Q000633:toxicity; D000818:Animals; D001711:Biotransformation / Q000528:radiation effects; D006224:Cricetinae; D003412:Cricetulus; D006639:Histidine / Q000378:metabolism; D008027:Light; D009152:Mutagenicity Tests; D012486:Salmonella typhimurium / Q000187:drug effects / Q000528:radiation effects
D006639:Histidine; D015127:9,10-Dimethyl-1,2-benzanthracene