METABOLISM-DEPENDENT ACTIVATION AND TOXICITY OF CHEMICALS IN NASAL GLANDS

The mucosae of the nasal passages contain a large amount of glands whi ch express secretory proteins as well as phase I and phase II biotrans formation enzymes. In this review the metabolic activation, covalent b inding and toxicity of chemicals in the Bowman's glands in the olfacto ry mucosa, in the sere-mucous glands in the nasal septum and in the la teral nasal glands and maxillary glands around the maxillary sinuses a re discussed. Light microscopic autoradiographic studies have demonstr ated a selective covalent binding of nasal toxicants and carcinogens s uch as halogenated hydrocarbons and N-nitrosamines, especially in the Bowman's glands following a single systemic exposure, suggesting a hig h rate of metabolic activation of chemicals in these glands. Special a ttention is put on the herbicide dichlobenil which induces necrosis in the olfactory mucosa following a cytochrome-P450-mediated metabolic a ctivation and covalent binding in the Bowman's glands. (C) 1997 Elsevi er Science B.V.