Potential initiating and promoting activities of diacetyl and glyoxal in rat stomach mucosa.

The potential initiating and promoting activities in the rat glandular stomach of the dicarbonyl compounds diacetyl (DA) and glyoxal (G), which are found in various heated foods, were studied. Administration of DA at doses of 300 to 1500 mg/kg body weight and of G at doses of 150 to 400 mg/kg body weight by gastric intubation to male F344 rats induced up to 100-fold increase in ornithine decarboxylase activity (formation of 195 pmol CO2/30 min/mg protein by DA and 302 pmol CO2/30 min/mg protein by G) with maxima after 16 hr. These treatments also induced a more than 10-fold increase in DNA synthesis (incorporation of 11,400 dpm of [3H]dThd/microgram DNA by DA and 15,100 dpm of [3H]dThd/microgram DNA by G) with maxima after 16 hr, and induced apparent unscheduled DNA synthesis in the pyloric mucosa of the stomach within 3 hr after administration. These results suggest that DA and G have potential tumor-promoting activities and may also have initiating activities in carcinogenesis in the glandular stomach.