title: Use of a reversion assay HGPRT- to HGPRT+ to demonstrate mutagenic adaptation in V79 Chinese hamster cells.
abstract: A reverse mutation assay HGPRT- to HGPRT+ has been used to demonstrate adaptation to the mutagenic effects of monofunctional alkylating agents. HGPRT- cells exposed to single doses of methylating or ethylating agents show maximum revertant frequencies immediately after treatment and these subsequently decline exponentially. Cells pre-treated with MNNG (1.0 microM) or MMS (0.27 mM) then challenged 6-168 h later with MNNG or EMS showed a consistent reduction in revertant frequencies. Pretreatment with EMS did not result in any reduction in EMS-induced reversion frequency. In parallel experiments no modifications in survival kinetics were observed. V79 cells do not remove O6-methylguanine and totally lack O6-methylguanine transferase activity, therefore other lesions and repair enzymes must be involved in the mutagenic adaptation observed.
mesh_terms: D000222:Adaptation, Physiological; D000477:Alkylating Agents / Q000633:toxicity; D000818:Animals; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D008769:Methylnitronitrosoguanidine; D009154:Mutation
chemical_list: D000477:Alkylating Agents; D008769:Methylnitronitrosoguanidine; D007041:Hypoxanthine Phosphoribosyltransferase