0000000000379131
AUTHOR
J.g. Filser
Biological activation of 1,3-butadiene to vinyl oxirane by rat liver microsomes and expiration of the reactive metabolite by exposed rats.
When 1,3-butadiene is incubated with rat liver microsomes and NADPH both enantiomers of vinyl oxirane are formed, the amount of epoxide being dependent on incubation time, microsomal protein, and substrate concentration. Inhibition by SKF 525 A or dithiocarb as well as induction by pretreatment with phenobarbital or 20-methylcholanthrene suggest participation of cytochrome P-450 in this reaction. The amount of epoxide is enhanced by addition of 1,1,1-trichloropropene oxide and reduced by glutathione, especially in the presence of hepatic cytosol. When rats are exposed to 1,3-butadiene in a closed chamber (conditions of maximal metabolism) vinyl oxirane is exhaled and can be quantitatively d…
Evidence of chloroethylene oxide being the reactive metabolite of vinyl chloride towards DNA: comparative studies with 2,2′ -dichloro-diethylether
The roles of chloroethylene oxide (CEO) and chloroacetaldehyde (CAA) in carcinogenicity of vinyl chloride (VC) have been studied by comparing biological effects of VC exposure with those of 2,2'-dichlorodiethylether (bis(chloroethyl)ether, BCEE) as a metabolic precursor of CAA. Biological end-points investigated were covalent protein binding, nucleic acid (RNA and DNA) alkylation and the potency of the two chemicals to induce preneoplastic ATPase-deficient foci in rat liver. After exposure of rats to [1-14C]BCEE, BCEE derived radioactivity was bound to liver proteins. Analysis of hydrolysates of liver RNA and DNA gave no indication for the formation of either 7-N-(2-oxoethyl)guanine, 1,N6-e…
Exhalation of ethylene oxide by rats on exposure to ethylene.
Abstract When rats are exposed to ethylene in a closed desiccator jar chamber, the rate of metabolic elimination of the compound is influenced by pretreatment with Aroclor 1254 (metabolism increased) and diethyldithiocarbamate (metabolism inhibited). Biotransformation of ethylene leads to ethylene oxide as reactive intermediate. This is exhaled and can be quantitated in the gas phase of the system.