Hippuric acid and methyl hippuric acid in rat hair: possible monitoring of xylene and toluene exposure.
Thinner is mainly composed of toluene and xylenes, and we studied the incorporation of the main metabolites of toluene and xylenes, hippuric acid (HA) and o-, m-, and p-methyl hippuric acids (o-, m-, p-MHA), in dark agouti rats' hair. Rat black hair was shaved before any exposure with an electric shaver designed for animals. Studies were performed in vivo with exposures of 30 min per day at three different concentrations (100, 300, and 1000 ppm) of toluene and o-, m-, and p-xylene for a total of 10 times over 2 weeks. Newly grown hair was tweezed out from the root with tweezers at seventh of the last exposure. Hair samples were then washed, extracted, derivatized, and analyzed by gas chromatography-mass spectrometry (GC-MS). HA and o-, m-, and p-MHA were not detected (ND) in the unexposed rat hair. After exposure, the metabolite concentration in the hair changed depending on the exposure concentration. Mean concentrations ranged from ND to 7.6 ng/mg, from ND to 13.8 ng/mg, from ND to 10.1 ng/mg, and from ND to 9.2 ng/ml hair for HA, o-, m-, and p-MHA, respectively. These results indicate that the metabolites concentrations in hair are effective indices of thinner exposure.
Department of Forensic Medicine, Tokai University School of Medicine, Bohseidai, Isehara, Kanagawa 259-1193, Japan. saito@is.icc.u-tokai.ac.jp
Takeshi
T
Saito
Takahiko
T
Kusakabe
Sanae
S
Takeichi
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006197:Hair / Q000737:chemistry*; D006626:Hippurates / Q000032:analysis*; D008297:Male; D011897:Random Allocation; D051381:Rats; D012997:Solvents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D014050:Toluene / Q000008:administration & dosage / Q000493:pharmacokinetics*; D014992:Xylenes / Q000008:administration & dosage / Q000493:pharmacokinetics*
D006626:Hippurates; D012997:Solvents; D014992:Xylenes; D014050:Toluene; C030514:hippuric acid