Identification of three sulphur-containing urinary metabolites of styrene in the rat.

1. After administration of styrene (1) to rat, three sulphur-containing urinary metabolites were isolated in the molar ratio of III : IV : V equal to 65 : 34 : 1. 2. These metabolites were identified as N-acetyl-S-(1-phenyl-2-hydroxyethyl)cysteine (III), N-acetyl-S-(2-phenyl-2-hydroxyethyl)cysteine (IV) and N-acetyl-S-(phenacyl)cysteine (V). 3. After a single dose (250 mg/kg, 2.4 mmol/kg) styrene, the totally excreted mercapturic acids in the urine amounted to 10.7 +/- 1.0% (n = 5) of the dose.