Status of glutathione in nasal epithelium

During inhalation exposure to air-born toxicants, the nasal epithelium may be subjected to local toxicity. Since glutathione (GSH) is often involved in xenobiotic metabolism, GSH status in these tissues has been examined. GSH content and apparent first-order rate constants for GSH content and apparent first-order rate constants for GSH turnover and synthesis were determined for respiratory epithelium covering the anterior ventral septum, olfactory epithelium covering the dorsal posterior septum, olfactory epithelium covering the dorsal meatus from male Fischer rats. The three tissues had similar concentrations of GSH (approximately 3-3.4 umol/g tissue) as determined by the Ellman's assay or by HPLC equipped with an electrochemical detector. Animals were administered [35S]Cysteine (Cys) by tail vein injection and rate constants were estimated, after incorporation of Cys into tissue GSH pools, by the decrease in GSH specific activity 1-102 hr after administration. Total [35S]GSH was analyzed by HPLC with a flow-through radioactivity detector. The three nasal epithelial tissues had similar apparent biphasic rates of GSH turnover, with rapid-phase half-lives of less than 10 hr and slow-phase half-lives of approximately 30 hr. The high GSH concentrations and the apparent rapid GSH turnover may facilitate the GSH-mediated detoxification within nasal tissue