Induction of mouse lung adenomas by amines or ureas plus nitrite and by N-nitroso compounds: effect of ascorbate, gallic acid, thiocyanate, and caffeine
Mirvish, S.S.; Cardesa, A.; Wallcave, L.; Shubik, P.
Journal of the National Cancer Institute 55(3): 633-636
1975
ISSN/ISBN: 0027-8874 PMID: 1159840 Document Number: 90009
The effects of ascorbic acid and gallic acid in inhibiting development of lung adenoma in male strain A mice owing to the action of nitrosamines were examined. Systems involving direct administration of nitrosamine in drinking water and ingestion of sodium nitrite in conjunction with amino compounds of physiological importance were studied; dose response curves for mononitrosopiperazine, N-nitrosomorpholine and methylnitrosourea in drinking water were found and the effect of the NaNO2 concentration in drinking water on tumour induction after nitrosation in vivo of morpholine and methylurea was studied also. When the effects of gallic acid, sodium thiocyanate and caffeine on the morpholine/nitrite system were tested, only gallic acid and caffeine were found to inhibit adenoma induction. Sodium ascorbate 11.5 or 23.0 g/kg diet reduced the incidence of adenoma by 89 to 98% in the systems involving NaNO2 and piperazine, morpholine and methylurea. The extent of nitrosation in vivo was estimated by comparing tumour incidence from direct administration of nitrosamines with that obtained by NaNO2/amine systems at various concentrations. For morpholine or methylurea with nitrite 2.0 g/litre the value was about 0.6%. In the morpholine/NaNO2 system, gallic acid and ascorbic acid were equally effective in inhibiting tumour formation.