132 



Scientific Proceedings (34). 



70 (408) 



On the decomposition of caffeine in the liver.' 



By W. 0. EMERY and WILLIAM SALANT. 



\_From the Laboratory for Synthetic Products and Pharmacological 

 Laboratory of the Burea7i of Chemistry, U. S. Dept. of 

 Agriculture, Washington, D. C] 



The earlier workers on the metabolism of caffeine and theo- 

 bromine maintained that these substances may undergo partial or 

 complete transformation in the body with the loss of one or more 

 of the methyl groups. Investigations carried out recently seemed 

 to indicate that this was due to specific enzymes. Schittenhelm, 

 Brugsch and Pincussohn ^ claimed to have found an enzyme in 

 the lungs of the horse capable of splitting off the methyl groups 

 of caffeine. Kotake^ came to similar conclusions as a result of 

 studies on the decomposition of caffeine in beef livers. He added 

 varying amounts of caffeine to aqueous extracts of the liver which 

 he allowed to digest under antiseptic precautions at body tempera- 

 ture in the thermostat for four days. Liver extracts without caf- 

 feine, similarly treated, were used as controls. At the end of each 

 period the purin bodies were precipitated and total nitrogen deter- 

 mined. He found in every case much larger amounts of total 

 nitrogen in the extract containing caffeine than in the control, from 

 which he concluded that the increase of purin substances was due 

 to the reduction of caffeine to non-methyllated purins. 



The work of Fuijitani^ has shown that caffeine stimulates 

 peptic digestion iti vitro. The possibility of a stimulating action 

 of caffeine on intra-cellular enzymes is therefore not to be excluded, 

 and might explain the results of Kotake. Moreover, in Kotake's 

 experiments no separation of the alkaloid was attempted. 



We therefore carried out a series of experiments in which the 

 caffeine as well as the purin nitrogen was determined. Finely 

 minced fresh beef livers were allowed to stand twenty four hours 

 in the presence of 5 c.c. toluol and were filtered through paper. 



1 Published by permission of the secretary. 



^ Cent. f. d. ges. Physiol, u. Path, des Stoffewechs, I908, ix, 290. 

 ^ Arch, internat. d. pharm. et de ther., 1905, xiv, 21. 

 * Zeit. f. physiol. Chem., I908, lix, 378. 



