title: Mechanism of the microsomal reduction of carbon tetrachloride and halothane.
abstract: The source of the hydrogen atoms in reduced metabolites of carbon tetrachloride and halothane has been studied. This was approached by measuring deuterium incorporation into chloroform and 2-chloro-1,1,1-trifluoroethane formed as microsomal metabolites of carbon tetrachloride and halothane, respectively, in a medium enriched in deuterium oxide. GC/MS analysis showed no deuterium enrichment of chloroform when hepatic microsomal fractions from control rats were used; however, small increases in enrichment were seen when microsomes from phenobarbital or benzpyrene-treated rats were employed. no detectable deuterium incorporation into 2-chloro-1,1,1-trifluoroethane was observed. These results suggest that carbanions are not formed as major intermediates and suggest that one-electron transfer reactions predominate in the reductive metabolism of carbon tetrachloride and halothane.
mesh_terms: D000818:Animals; D001580:Benzopyrenes / Q000494:pharmacology; D001711:Biotransformation; D002251:Carbon Tetrachloride / Q000378:metabolism*; D002725:Chloroform / Q000096:biosynthesis; D003903:Deuterium; D008401:Gas Chromatography-Mass Spectrometry; D006221:Halothane / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D010084:Oxidation-Reduction; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats
chemical_list: D001580:Benzopyrenes; D002725:Chloroform; D006859:Hydrogen; D003903:Deuterium; D002251:Carbon Tetrachloride; D006221:Halothane; D010634:Phenobarbital