FORMATION OF N-NITROSAMINES FROM SECONDARY AMINES AND NITRITE IN HUMAN AND ANIMAL GASTRIC JUICE

A study was made of the possible formation of diethylnitrosamine (DEN) from nitrite and diethylamine in the acidic environment of the stomach of humans and various laboratory animals. The in vitro formation of DEN was demonstrated when diethylamine and sodium nitrite were incubated with gastric juices from rats, rabbits, cats, dogs and man. Human and rabbit juices (pH 1-2) produced more DEN than did rat gastric juice (pH 4-5). The nitrosation reaction has been shown to occur in vivo in cats and rabbits. The yields of DEN were low but the identity of the DEN formed was confirmed by both thin-layer and gas chromatography. The possible formation of traces of nitrosamines over a prolonged period under the acid conditions prevailing in the stomach could constitute a hazard to human health. It is suggested that, for the further tests necessary to establish whether a significant hazard does exist, the rabbit, cat or ferret, with gastric juices similar in pH to that of man, may be more suitable test species than the rat. © 1969 Pergamon Press Limited.