title: Toxicity of a sevoflurane degradation product incubated with rat liver and renal cortical slices.
abstract: Compound A (2-fluoromethoxy-1,1,3,3,3-pentafluoro-1-propene) is a degradation product of the anesthetic sevoflurane which is created in closed-circuit anesthetic machines. Past in vivo and in vitro studies have implied that Compound A is nephrotoxic via bioactivation through the cysteine conjugate beta-lyase pathway. Although glutathione (GSH) conjugates of Compound A have been reported, it is not clear if they are formed enzymatically or via direct reaction with GSH. To determine if these metabolites are produced and toxic, a tissue slice system that first exposes male Fischer 344 rat liver slices to volatilized Compound A followed by exposure of rat kidney slices to the liver incubate was employed. Liver slices exposed to volatilized Compound A (6-12 microM medium conc.; approximately 23 ppm) exhibited a loss of K+ by 6 h, which was not seen in kidney slices exposed to Compound A. Aminobenzotriazole, a cytochrome P 450 suicide inhibitor, initially inhibits the cytotoxicity of Compound A to liver slices (at these times and concentrations). The sequential liver/kidney slice experiments using Compound A have not demonstrated nephrotoxic results. GSH conjugates were synthesized and was found to be nephrotoxic at concentrations above 91 microM (18 h), with higher concentrations showing toxicity at earlier times. Additionally, non-enzymatic reactions of Compound A with GSH or sulfhydryl-containing medium produces nephrotoxic products. These studies show that Compound A is directly toxic to the liver, possibly via P 450 activation, and Compound A can react with sulfhydryls directly to produce a nephrotoxic.
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Catania
authors.forename: A R
authors.initials: AR
authors.lastname: Parrish
authors.forename: A J
authors.initials: AJ
authors.lastname: Gandolfi
mesh_terms: D018685:Anesthetics, Inhalation / Q000633:toxicity*; D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D004987:Ethers / Q000633:toxicity*; D005978:Glutathione / Q000378:metabolism; D006845:Hydrocarbons, Fluorinated / Q000633:toxicity*; D066298:In Vitro Techniques; D007672:Kidney Cortex / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008738:Methyl Ethers / Q000633:toxicity*; D051381:Rats; D011916:Rats, Inbred F344; D000077149:Sevoflurane
chemical_list: D018685:Anesthetics, Inhalation; D004987:Ethers; D006845:Hydrocarbons, Fluorinated; D008738:Methyl Ethers; D000077149:Sevoflurane; C078742:fluoromethyl 2,2-difluoro-1-(trifluoromethyl)vinyl ether; D005978:Glutathione