Distribution and reactivity of inhaled 14C-labeled toluene diisocyanate (TDI) in rats.
Kennedy-AL; Wilson-TR; Stock-MF; Alarie-Y; Brown-WE
Arch Toxicol 1994 Jul; 68(7):434-443
The biochemical events following inhalation exposure to toluene- diisocyanate (584849) (TDI) in a rat model were characterized to aid the interpretation of the carcinogenic risk. Male Fischer-344-rats were exposed head only to vapors of TDI at exposure levels of 0.026 to 0.821 parts per million (ppm) for 4 hours. All tissues studied showed detectable quantities of radioactivity with the airways, gastrointestinal system and blood having the highest levels which increased with exposure concentration. The concentration in the bloodstream after exposure was linear with respect to dose. Most of the label associated with the blood was recovered in the plasma, and of this, 97 to 100% of the carbon-14 existed in the form of biomolecular conjugates. Stomach content analysis indicated that the majority of the label was also associated with high molecular weight species. Over the vapor exposure and time tested, the authors concluded that conjugation was the predominant reaction and that free toluenediamine (25376458) (TDA) was not a primary in-vivo reaction product under these conditions.
NIOSH-Publication; NIOSH-Grant; Grants-other; Laboratory-animals; Metabolic-study; Isocyanates; Lung-irritants; Blood-analysis; Tissue-distribution; Body-burden; Dose-response; Inhalation-studies
Biological Sciences Carnegie-Mellon University 4400 Fifth Ave Pittsburgh, PA 15213
Other Occupational Concerns; Grants-other
Archives of Toxicology
Carnegie-Mellon University, Pittsburgh, Pennsylvania