164 ADVENTURES IN RADIOISOTOPE RESEARCH 



part of the acid-soluble P of the plasma does not get into exchange 

 equilibrium with the injected inorganic phosphorus. 



Our results do not contradict those of Govaerts. Phosphate identi- 

 fied after treatment of the plasma with trichloracetic acid as inorganic 

 phosphate but actually present in the plasma in a labile low molecular 

 organic binding may show a similar electrodialytic behaviour as does 

 inorganic phosphate. Proofs of the presence of a labile phosphorus com- 

 pound in the plasma is yet outstanding. 



Suniniary 



To determine whether inorganic labelled phosphate added to plasma gets into 

 ■exchange equilibrium with inorganic phosphate present previously, labelled 

 phosphate of negligible weight was added to huinan plasma. The plasma was 

 electrodialysed, samples were taken from the dialysator at intervals, their inorga- 

 nic phosphorus content and its radioactivity determined. 



No pronounced difference was found in the rate of disappearance of the inorga- 

 nic P content and of the radioactivity of the sample. As, however, after the lapse 

 of 18 hours, only 4% of the original activity, but 10% of the original inorganic P 

 content were present, we have to conclude that a small percentage of the plasma 

 inorganic phosphate, possibly combined with proteins, docs not interchange with 

 the labelled phosphate added. 



References 



J. Govaerts (1943) Bull. Acad. Med. Belg. (6), IX. 



J. Govaerts (1948) Arch. Int. Pharmacodyn. 75, 201. 



A. Grollman (1927) J. Biol. Chem. 72, 565. 



L. Hahn and A. Tiselius (1943) Biochem. Z. 314, 336. 



M. Macheboeuf, M. S0RENSEN and S. P. L. Sorensen (1925 — 1927) Medd. 



Carlsherg Lab. 16, No. 12. 

 F. C. Mclean and M. A. Hindrichs (1938) Amer. J. Physiol. 121, 580. 

 A. V. Masket, a. Chanulin and S. Ludevig (1942). J. Biol. Chem. 143, 763. 

 C. L. A. Schmidt and D. M. Greenberg (1935) Physiol. Rev. 15, 297. 

 P. K. Smith, R. W. Ollayos and A. W. Winkler (1943) J. Clin. Inv. 22, 1431. 

 S. P. L. S0BENSEN (1925—1927) Medd. Carlsherg Lab. 16, No. 8. 



