RENEWAL OF ACID SOLUBLE PHOSPHORUS COMPOUNDS IN OKGANS OF RABBIT 379 



of triosephophate. The last mentioned compound reading with pyruvic 

 acid forms phosphoglyceric acid which is converted into phosphopyruvic 

 acid and this, in turn, reacts with adenylic acid in tlie resynthesis of 

 adenosintriphosphate. The last mentioned compound is also formed by 

 direct phosphorylation of adenylic acid from inorganic phosphate or by 

 transfer of the phosphate radical of glycerophosphate to adenylic acid. 

 The synthesis of adenosintriphosphate is a very rapid process and the 

 active inorganic phosphate ions which penetrate into the corpuscles 

 will soon be found to be incorporated in adenosintriphosphate molecules. 

 The participation of the active adenosintriphosphate molecules in the 

 synthesis of various organic P compounds will lead to the formation 

 of active hexosephosphate, active phosphoglyceric acid, and so on, 

 in the corpuscles. In this connection, the result obtained by Dische^^^ 

 is of interest : he found that the total phosphate transferred to glucose 

 added to human erythrocytes originates from adenosintriphos- 

 phate. 



Important evidence that the organic acid soluble phosphorus com- 

 pounds and, primarily, diphosphoglycerate of the red blood corpuscles 

 constitute a labile phosphorus reserve of considerable consequence, 

 serving various functions was presented in recent years by Guest and 

 his colleagues®. Some of their findings are described in what follows. 



The development of rickets in rats is associated with decreases in 

 all fractions of the acid soluble phosphorus. During the first five days, 

 the concentration of inorganic phosphorus and adenosintriphosphate 

 phosphorus drops abruptly to a low level and then remains constant 

 for 25 days and longer. The decrease in the organic acid soluble phos- 

 phorus is accounted for almost entirely, after the first few days, in the 

 diphosphoglycerate fraction. Guest and Rappaport state that diphos- 

 phoglycerate makes out about half of the acid soluble phosphorus pre- 

 sent in the corpuscles. 



In experiments carried out on dogs after nephrectomy, it was found 

 that, due to the failure of excretion of the vaste endogenous P, a large 

 increase in the inorganic P content of the blood takes place, which is 

 followed by a corresponding increase in the acid soluble organic P content 

 of the corpuscles. The increase is mainly due to the rise of the diphospho- 

 glycerate content of the corpuscles, the increase in organic acid soluble 

 P and in diphosphoglycerate P being 47 and 43 mgm, respectively, 

 per hundred cc. 



They found, furthermore, that the increase of phosphorus excretion 

 in the urine during acidosis comes partly from mobilised diphospho- 



iZ. DiscHE, Naturwiss. 24, 462 (193G). 



(2) A summary of many of their results is to be found in tlic^ paper by G. M. 

 Guest and S. Rappapokt, Amer. J. Dis. Children 58, 1072 (1939). 



