Inhalation of 1-nitropyrene associated with ultrafine insoluble particles or as a pure aerosol: comparison of deposition and biological fate
The direct-acting mutagen, (/sup 3/H)nitropyrene (/sup 3/H-NP), was used as a model nitroaromatic compound. Rats were exposed to this radiolabeled compound by nose-only inhalation either as a coating (approx. 6% by mass) on relatively inert, ultrafine /sup 67/Ga/sub 2/O/sub 3/ particles or as a homogenous ultrafine aerosol. The tissue deposition, retention, and biological fate of each aerosol were investigated and compared. Respiratory tract clearance of /sup 3/H radioactivity from each exposure was very rapid with no apparent differences seen in the lung retention of this inhaled compound between each exposure over the course of these studies. Higher /sup 3/H-radioactivity levels were seen in stomach and large intestines of rats exposed to the /sup 67/Ga/sub 2/O/sub 3/-associated /sup 3/H-NP than in the same tissues from rats exposed to the pure /sup 3/H-NP aerosol. Rats exposed to the /sup 3/H-NP-/sup 67/Ga/sub 2/O/sub 3/ aerosol excreted the majority of the deposited /sup 3/H radioactivity in the feces (75 +/- 18%), whereas pure /sup 3/H-NP exposed animals excreted a major portion of the radiolabel in the urine (76 +/- 18%). It appeared that the major portion of the pure /sup 3/H-NP aerosol was cleared from the respiratory tract by direct absorption into blood, while the /sup 67/Ga/sub 2/O/sub 3/-associated /sup 3/H-NP was cleared by both blood absorption and mucociliary clearance followed by ingestion and fecal excretion. The differences in the deposition and biological fate between the particle-associated NP and the pure NP aerosol may have important implications in terms of the metabolic fate of inhaled nitroaromatic compounds and the health risks associated with human exposures to particulate environmental pollutants that contain this class of compounds.
- Research Organization:
- Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM
- DOE Contract Number:
- AC04-76EV01013
- OSTI ID:
- 6829987
- Journal Information:
- Toxicol. Appl. Pharmacol.; (United States), Vol. 69
- Country of Publication:
- United States
- Language:
- English
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560305* - Chemicals Metabolism & Toxicology- Vertebrates- (-1987)