METABOLIC CAPACITY OF NASAL TISSUE INTERSPECIES COMPARISONS OF XENOBIOTIC-METABOLIZING ENZYMES

High levels of xenobiotic-metabolizing enzymes occur in the nasal muco sa of all species studied. In certain species, including rats and rabb its, unique enzymes are present in the nasal mucosa. The function of t hese enzymes is not well understood, but it is thought that they play a role in protecting the lungs from toxicity of inhalants. The observa tion that several nasal xenobiotic-metabolizing enzymes accept odorant s as substrates may indicate that these enzymes also play a role in th e olfactory process. Xenobiotic-metabolizing enzymes were found in the nasal cavity around 15 years ago. Since that time, much has been lear ned about the nature of the enzymes and the substrates they accept. In the present review, this information is summarized with special atten tion to species differences in xenobiotic-metabolizing enzymes of the nasal cavity. Such differences may be important in interpreting the re sults of toxicity assays in animals because rodents are apparently mor e susceptible to nasal toxicity after exposure to inhalants than are h umans. (C) 1997 Elsevier Science B.V.