482 



ADVENTURES IN RADIOISOTOPE RESEARCH 



and the specific activity of the corpuscles P at the end of the experiment 



S^ = a (0.5 Sp -0.9S,)t. 



S 

 The value of a being known (a = 0.0010), the quantity— 1 can be 



Sp 

 evaluated. The figures thus obtained and also those supplied l)y the 

 experiment are recorded in Table 4. 



Table 4 



UPTAKE OF PHOSPHATE IONS BY THE BLOOD CORPUSCLES IN 



EXPERIMENTS IN VIVO 



The interpretation of the results of experiments in vivo is much com- 

 plicated by the fact that active phosphate introduced into the blood 

 stream is rapidly exchanged with phosphate of bone tissue. Such an 

 interaction leads to a very rapid decrease in the activity of the blood after 

 intravenous administration of active phosphate as the specific activity 

 of the plasma inorganic P at the end of the experiment differs very 

 strongly from the value prevailing on the average during the experiment. 

 To facilitate the interpretation of the result the labelled sodium phosphate 



Table 5. — Percentage of the Total Labelled 

 P Injected During the Course of the Experi- 

 ment Present in the Circulation 



(Labelled .sodium phosphate administered drop by 

 drop in the course of three hours) 



