Sites of metabolism of N-nitrosodiethylamine in mice.

Low-temperature whole-body autoradiography and autoradiography with heated sections in C57Bl mice injected with N-[14C]nitrosodiethylamine showed a homogenously distributed volatile radioactivity in most tissues--indicating an ability of the non-metabolized substance to freely pass the biological membranes and distribute evenly in the intra- and extracellular tissue-water. A high level of non-volatile metabolites was found in several tissues: the nasal and tracheal mucosa, the mucosa of the bronchial tree, the salivary glands, the liver, the mucosa of the oesophagus and the tongue, and the lacrimal glands. Studies in vitro indicated that these tissues had a capacity to degrade N-[14C]nitrosodiethylamine (14CO2-production and incorporation of radioactivity in the acid-insoluble material of the tissues were used as indices of the metabolism), whereas several other tissues, which did not accumulate metabolites at short survival intervals in vivo, were devoid of significant metabolic capacity. The relationship between metabolic ability and carcinogenic response of the tissues for N-nitrosodiethylamine is discussed on basis of the obtained results.