476 



ADVENTURES IN RADIOISOTOPE RESEARCH 



reaction between inorganic phosphate ions and the hydrolysable esters 

 is a very fast process. That the inorganic P present in the corpuscles 

 does not reach exchange equilibrium with the plasma phosphate in the 

 course of a few hours is due to the fact that a large part of the active 

 phosphate ions are incorporated into the organic compounds of the 

 corpuscles, while simultaneously non-active phosphate ions are freed to 

 take place of the active ones and "dilute" the active inorganic phosphate 



Fig. 1. 



Ilatio of the specific activities of the total acid- soluble phosphate 



and the inorganic phosphate present in the corpuscles. 



X = Rabbit G. O = Rabbit H. 



which penetrated into the corpuscles, diminishing thus the specific 

 activity of the corpuscle inorganic P. 



If the whole ester-phosphorus could exchange with the inorganic P, 



the activity-ratio should finally reach a value 1.0 (indicated by the 



g 



dotted line). It is clear that the hmiting value of --^ is much lower, which 



is due to the presence of an organic phosphorus fraction in the corpuscles 

 exchanging at a slow rate. 



PENETRION OF PLASMA HPO4 INTO CORPUSCLES 



We may obtain information as to the rate of penetration of the HPO 

 from the plasma into the corpuscles by comparing, after a lapse of time, 

 the specific activities of the plasma inorganic P and that of the total 

 acid-soluble P present in the corpuscles. An alternative method would 

 be to compare the specific activities of the plasma inorganic P and the 



