STUDIES ON THE METABOLISM OF I'HOSPHOIUS IX ANIMALS 



\y.\ 



PHOSPHORUS EXCHANGE IN ADULT RATS 



A preliminary investigation revealed the following distribution in 

 adult rats killed three weeks after eating the radioaelive phosphate 

 administered in the lorin of (1.5 mgm sodium phosphate added to the 

 normal diet. 



Table 4. — Distribution of Rad. P 



IN Adult Rats Killed 3 Weeks 



AFTER Eating it 



p. c. rad. 1' 



Uiiiic 26.3 



Faeces i 31.S 



Skeleton | 24.8 



Muscles and fat 17.4 



Liver 1-7 



Brain and Medulla 0.1 



Kidneys and Pancreas .... | 0.1 



In interpreting the results obtained it is convenient lo compare the 

 radioactivity of equal weights (say 100 mgm) of the ashes, of the bones, 

 the teeth, the liver, and so on. These all contain about the same percent- 

 age of phosphorus (17 per cent, 17 per cent, 16 per cent); the phos- 

 phorus content of the ash of the blood is rather different, but as was 

 stated above the behaviour of the active phosphorus in the blood was 

 not investigated to any great extent in the course of this work. 



In a series of experiments we gave the same amount of radioactive 

 phosphorus to 6 rats. One pair of rats was killed after one week, a second 

 pair after two weeks, and a third pair after three weeks. The results 

 are seen in the following table. 



The weights of the different skeletons vary to an appreciable extent; 

 the weights of the animals were 225, 210, 200, 215, 235 and 220 gm 

 before, and 220, 205, 200, 205, 235 and 220 gm resp. after Ihe experi- 



Tablk r, 



AjiinuU killeil weeks after 

 eating rad. P 



p. I', of rad. i' found 



in the skeleton in the incisors 



