340 VII. ACIDS, AMIDES, ALDEHYDES AND HYDROCARBONS 



to Parke and Williams, ^-'^ the following l)alance sheet can be drawn up 

 when benzene is fed at 0.5 g./kg. 



Benzene eliminated unchanged 39% 



Benzene oxidized (excreted as glucuronides or as ethereal sulfates) 21% 



Benzene excreted as phenylmercaptvu'ic acid 1% 



After C^Mabeled benzene was fed to rabbits, Parke and Williams ^^* 

 were able to account for 0.5% of the dose administered as radioactive l- 

 phenylmercapturic acid. Although phenylmercapturic acid would appear 

 to be a minor detoxication product of benzene, there can be no doubt 

 that it plays a definite role in this reaction. 



Table 2 



The Metabolic Fate of a Single Oral Dose of C '^-Labeled Benzene in a Rabbit 

 Two TO Three Days After Dosing" 



Individual 



' ■ • determination Total in 



(average), each category, 



Nature of metabolite % of dose % of dose 



In expired air 



Unchanged benzene 43 . 



Respiratory COa 1.5 



Total — 44.5 

 In urine 



Phenol* . 23.5 



Catechol* 2.2 



Quinol* 4 . 8 



Hydro.xyquinol'' . 3 



Muconic acid' 1 . 3 



L-Phenylmercapturic acid 0.5 



(urinary radioactivity) (34.5) 



Total — 32 . 

 In tissues 



Metabolized benzene 4 . 5-9 .5 4 . 5-9 . 5 



In feces 0.5 0.5 

 Total accounted for 



In expired air and urine 77 79 



In all sources 82-87 84-89 



° Adapted from D. V. Parke and R. T. Williams, Biochem. J., 64, 231-238 (1954), p. 

 236. 



* Excreted in conjugated form. 

 "^ Trans-lrans acid. 



g'. Resume of the Metabohsm of Benzene: There is ample evidence 

 that benzene can be metabolized in the body by oxidation to phenol, 

 catechol, quinol, and hydroxyquinol. These intermediates can be con- 



