INCORPORATION OF CARBON-ATOMS FROM GLUCOSE INTO THE FOOD MUTAGENS MEIQX AND 4,8-DIMEIQX USING C-14-LABELED GLUCOSE IN A MODEL SYSTEM

Mixtures of creatinine, glucose and threonine with the addition of a s mall amount, 250 muCi, of [U-C-14]glucose, [1-C-14]glucose or [6-C-14] glucose were heated at 180-degrees-C for 30 min in an aqueous model sy stem. The mixtures were purified and analysed using HPLC, scintillatio n and Ames tests. 2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx ) and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) w ere detected as the main radioactive mutagens. The amount of MeIQx and 4,8-DiMeIQx produced from threonine was estimated at 18 and 60 nmol/m mol glucose respectively. Radioactive carbon atoms originating from gl ucose were also shown to be incorporated into 2-amino-3-methylimidazo[ 4,5-f]quinoxaline (IQx). The specific activity was calculated to be 0. 6, 0.3 and 0.1 - 0.3 mCi/mmol for MeIQx, 4,8-DiMeIQx and IQx respectiv ely for all three labelled forms of glucose. By the incorporation of c arbon atoms originating from glucose into the imidazoquinoxaline mutag ens it was clearly demonstrated that glucose is a precursor in the for mation of these food mutagens.