Toxicokinetics of ethers used as fuel oxygenates.
The toxicokinetics and biotransformation of methyl-tert.butyl ether (MTBE), ethyl-tert.butyl ether (ETBE) and tert.amyl-methyl ether (TAME) in rats and humans are summarized. These ethers are used as gasoline additives in large amounts, and thus, a considerable potential for human exposure exists. After inhalation exposure MTBE, ETBE and TAME are rapidly taken up by both rats and humans; after termination of exposure, clearance by exhalation and biotransformation to urinary metabolites is rapid in rats. In humans, clearance by exhalation is slower in comparison to rats. Biotransformation of MTBE and ETBE is both qualitatively and quantitatively similar in humans and rats after inhalation exposure under identical conditions. The extent of biotransformation of TAME is also quantitatively similar in rats and humans; the metabolic pathways, however, are different. The results suggest that reactive and potentially toxic metabolites are not formed during biotransformation of these ethers and that toxic effects of these compounds initiated by covalent binding to cellular macromolecules are unlikely.
Dekant
W
W
Department of Toxicology, University of Würzburg, Versbacher Str. 9, 97078 Würzburg D, Germany. dekant@toxi.uni-wuerzburg.de
Bernauer
U
U
Rosner
E
E
Amberg
A
A
D000393:Air Pollutants / Q000378:metabolism / Q000493:pharmacokinetics* / Q000633:toxicity; D000818:Animals; D001711:Biotransformation; D005019:Ethyl Ethers / Q000378:metabolism / Q000493:pharmacokinetics* / Q000633:toxicity; D006801:Humans; D019570:Inhalation Exposure; D007700:Kinetics; D008738:Methyl Ethers / Q000378:metabolism / Q000493:pharmacokinetics* / Q000633:toxicity; D051381:Rats; D012119:Respiration; D014018:Tissue Distribution; D001335:Vehicle Emissions
D000393:Air Pollutants; D005019:Ethyl Ethers; D008738:Methyl Ethers; D001335:Vehicle Emissions; C043243:methyl tert-butyl ether; C098546:ethyl tert-butyl ether; C096680:tertiary-amyl methyl ether