title: Changes of n-hexane metabolites in urine of rats exposed to various concentrations of n-hexane and to its mixture with toluene or MEK.
abstract: It is well known that n-hexane produces peripheral neuropathy, and 2,5-hexanedione, one of the metabolites of n-hexane, is thought to be the main causative agent. Recently, the metabolites of n-hexane in urine have been measured by gas chromatography, and 2,5-hexanedione was proved to be useful for the biological monitoring of n-hexane exposure. In the present experiment, we intended to clarify the change of n-hexane metabolites in the urine of rats exposed to various concentrations of n-hexane and to its mixture with toluene of MEK. In the first experiment, five separate groups of five rats each were exposed to 100, 500, 1000, or 3000 ppm of n-hexane, or fresh air respectively in an exposure chamber for 8 h a day. Urinary samples were gathered during exposure, 16, 24, and 40 h after exposure. Half of each sample was analyzed by gas chromatography after hydrolysis with acid and enzymes, and the other half was analyzed without hydrolysis. 2,5-Dimethylfuran, MBK, 2-hexanol, 2,5-hexanedione, and gamma-valerolactone could be identified as n-hexane metabolites in the urine. The main metabolites were 2-hexanol and 2,5-hexanedione. 2-Hexanol was mostly excreted during exposure, while most of the 2,5-hexanedione was excreted after the end of exposure. The amount of metabolites in the urine correlatively increased with the concentration of n-hexane from 100 to 1000 ppm, but the amount of metabolites scarcely increased when the concentration of n-hexane increased from 1000 to 3000 ppm.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D002074:Butanones / Q000633:toxicity*; D005663:Furans / Q000652:urine; D006586:Hexanes / Q000378:metabolism / Q000633:toxicity*; D000441:Hexanols / Q000652:urine; D006588:Hexanones / Q000652:urine; D007783:Lactones / Q000652:urine; D008297:Male; D008742:Methyl n-Butyl Ketone / Q000652:urine; D051381:Rats; D011919:Rats, Inbred Strains; D014050:Toluene / Q000633:toxicity*
chemical_list: D002074:Butanones; D005663:Furans; D006586:Hexanes; D000441:Hexanols; D006588:Hexanones; D007783:Lactones; C026385:n-hexane; D014050:Toluene; C005222:methylethyl ketone; D008742:Methyl n-Butyl Ketone; C037076:2-hexanol; C011269:2,5-hexanedione; C037555:2,5-dimethylfuran; C037556:gamma-valerolactone