Effects of carcinogens and partial hepatectomy upon the hepatic O6-methylguanine repair system in mice.
The enhanced repair of O6-methylguanine from hepatic DNA in rats is a well established phenomenon that can be induced by pretreatment with a variety of hepatotoxic agents as well as by partial hepatectomy. Attempts to induce a similar hepatic response by treatment with single doses of aflatoxin B1 in C57Bl mice, single doses of dimethylnitrosamine (DMN) in C57Bl or BALB/C mice or by prolonged pretreatment with DMN by addition to the drinking water of C57Bl mice were uniformly unsuccessful. Furthermore, the intense proliferative response induced by two-thirds partial hepatectomy in C57Bl mice was also apparently incapable of increasing the activity of this repair function. These experiments, in which repair of O6-methylguanine has been determined both in vivo after administration of [14C]DMN and in vitro using crude tissue extracts and a methylated DNA substrate, indicate the presence of an intergeneric difference between rats and mice with respect to this repair function.
D016604:Aflatoxin B1; D000348:Aflatoxins / Q000494:pharmacology; D000818:Animals; D002273:Carcinogens / Q000494:pharmacology*; D002474:Cell-Free System; D004247:DNA / Q000096:biosynthesis; D004260:DNA Repair / Q000187:drug effects*; D004128:Dimethylnitrosamine / Q000494:pharmacology; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism; D006498:Hepatectomy; D008099:Liver / Q000502:physiology*; D008115:Liver Regeneration; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D051381:Rats; D011919:Rats, Inbred Strains
D000348:Aflatoxins; D002273:Carcinogens; D006147:Guanine; D004247:DNA; C008449:O-(6)-methylguanine; D016604:Aflatoxin B1; D004128:Dimethylnitrosamine