58 



Scientific Proceedings (47). 



40 (649) 



Tho elimination and toxicity of caffein in nephrectomized 



rabbits. 



By W. SALANT and J. B. RIEGER. 



[Presented by permission of the Secretary of Agriculture.] 



In experiments on the elimination of caffein in rabbits and 

 guinea pigs carried out by the writers 1 in this laboratory recently 

 it was found that much larger amounts of caffein were recovered 

 from the gastro-intestinal canal when these animals were fed oats 

 than when carrots were given. Since greater quantities of urine 

 are secreted on a diet of carrots than on one of oats, it seemed 

 probable that the excretory function of the gastro-intestinal canal 

 might be stimulated to greater activity in order to compensate for 

 the diminished diuresis when oats were fed. The elimination of caf- 

 fein into the gastro-intestinal canal after the removal of both kid- 

 neys ought to be greater, therefore, than in normal animals. 



In experiments which were performed with caffein which was 

 given subcutaneously to rabbits after double nephrectomy, the fol- 

 lowing results were obtained: The amounts recovered at the end 

 of about 22 hours from the contents of the stomach and intestines 

 varied between 7.7 per cent, and 11.78 per cent., which is two to 

 three times greater than was found in normal rabbits, much larger 

 amounts being present in the intestines than in the stomach. In 

 one rabbit which died seven hours after caffein was injected sub- 

 cutaneously, about io| per cent, were recovered from the intestines 

 and about half this amount was obtained from the contents of the 

 stomach. 



The total amount of caffein eliminated in nephrectomized 

 rabbits in about 22 hours was approximately equal to that elimi- 

 nated by the gastro-intestinal canal and kidneys combined of normal 

 rabbits during an equal period of time, thus showing that the 

 stomach and intestines acquire much greater power of elimination 

 after the kidney is removed. 



Observations were also made on the toxicity of caffein in nephrec- 

 tomized rabbits. The results obtained showed that the resistance 



'Bull. 157, Bur. of Chemistry. 



