Carcinogenicity of N'-nitrosonornicotine in Sprague-Dawley rats

N'-Nitrosonornicotine was added to the drinking water of outbred Sprague-Dawley rats. Adenocarcinomas of the olfactory epithelium occurred in all 15 rats, squamous papillomas o- the esophagus in 1, squamous papillomas of the nonglandular stomach in 1, and a hepatacellular tumor in 1. The possible ingestion and subsequent in vivo nitrosation of nicotine and/or nornicotine could create a serious carcinogenic hazard to cigarette smokers.