TURNOVER OF LECITHIN, CEPHALIN AND SPHINGOMYELIN 



3:}i 



myelin was precipitated. A further purification of this product was 

 obtained by repeating the procedure described above. When sufficient 

 amounts were available, the sphingomyeltn was recrystalUsed from pyridin. 



Experiments with rabbits 



In the experiments, the results of which are given in Tables 15 and 

 16, all the labelled phosphate was administered at the start of the expe- 

 riment. In all later experiments, labelled phosphate was administered 



Table 15. — Specific Activity of Inorganic P and of 

 Different Phosphatide Fractions 

 Rabbit X. — Weight: 2.9 kgm 

 All labelled phosphate was administered at the start of the experi- 

 ment by stomach tube. The animal was killed after 19 houi-s 



Table 16. — Specific Activity of Inorganic P and P of 

 Different Phosphatide Fractions 

 Rabbit XI. — Weight: 2.2 kgm 

 Labelled phosphate administered to the rabbit by subcuta- 

 neous injection at the start of the experiment. — The animal 

 was killed after the lapse of 7 days 



Fraction 



Relative specific 

 activitv 



Plasma lecithin P 



Plasma cephalin P 



Plasma sphingomyelin P 

 Corpuscles lecithin P . . . 

 Corpuscles cephalin P . . 



Brain inorganic P 



Brain lecithin P 



Brain cephalin P 



100 

 48.1 

 74..-) 

 88.5 

 73.1 

 26.6 

 14.1 

 20.9 



