The formation of phenylethane-1,2-diol 2-acetate in the metabolism of styrene oxide by rabbit liver microsomes in vitro.

1. Phenylethane-1,2-diol 2-acetate has been isolated from the incubation of styrene oxide or styrene diol with liver microsomes of phenobarbital-pretreated rabbits. 2. Observed ratios of phenylethane-1,2-diol to its 2-acetate in the incubation mixtures ranged between 19 : 1 and 5 : 1 with different microsomal preparations and different periods of incubation. 3. The formation of phenylethane-1,2-diol 2-acetate may be a source of errors in the radiometric determination of epoxide hydrase activity in microsomes.