Subchronic inhalation of diethylamine vapor in Fischer-344 rats: organ system toxicity.

Male and female Fischer 344 (F-344) rats were exposed at 0,25 or 250 ppm diethylamine (DEA) vapor, 6.5 hr per day, 5 days per week, for 24 weeks in order to assess cardiac and other organ system toxicity. Scheduled sacrifices were performed following 30, 60, and 120 days of exposure. During the first 2 weeks of exposure, the rats exposed at 250 ppm DEA did not gain weight. After 2 weeks, however, the rate of weight gain of these rats was greater than that of controls. Nevertheless, mean body weights for both sexes of rats exposed at 250 ppm DEA remained depressed compared to controls throughout the study. Sneezing, tearing, and reddened noses were seen in rats exposed at 250 ppm DEA. Histopathologic examinations revealed lesions of the nasal mucosa of rats exposed at 250 ppm DEA (rats exposed at 25 ppm were not evaluated). These lesions of the respiratory epithelium consisted of squamous metaplasia, suppurative rhinitis, and lymphoid hyperplasia. There were no pronounced treatment-related effects on organ weights, hematology, or clinical chemistry indices except for blood urea nitrogen which was evaluated in rats of both sexes exposed at 250 ppm DEA for 24 weeks. In contrast to the high-dose animals, no treatment-related effects were observed in rats intermittently exposed at 25 ppm DEA for up to 24 weeks. No evidence of cardiotoxicity was seen in rats exposed to either DEA concentration for up to 24 weeks.