284 



ADVE.VTURES IN RADIOISOTOPE RESEARCH 



putting an appreciable strain on the lecithin circulation. A strain which would 

 be still more pronounced in the case of a lower plasma lecithin content. 



Table 10. — Phosphatide P in Plasma and Cells or 

 Different Animals 



mgm % P in 



I'lasmii 



Cell 



Ratio 



cell 



plasma 



Rat 



Ral)bit 



Man 



Dog 



Laying hen 



2.6 

 3.3 



9 

 14 

 14—20 



10 

 12 

 19 

 14 

 8—23 



3.S 

 3.(i 

 2.1 

 I 



0.87 



Protein phosphorus in the hen^s blood 



After removal of the phosphatides and the aciid soluble phosphorus, the remain- 

 ing P is generally assumed to be present as protein P. The protein P content 

 31.8 mgm% found in the corpuscles of the hen in the 28 hours experiment is much 

 higher than in the corpuscles of the blood of other animals, the corpuscles of the 

 rabbit containing for example, as found by Mr. Aten, 4.4 mgm %. The same 

 considerations apply to the protein P content of the plasma, which was found 

 to amount to 9.4 mgm% for the blood of the hen in question and of 7 mgm % in 

 the case of the hen discussed on page 276 while the plasma of a rabbit, for example, 

 was found to contain only 0.03 mgm % piotein P. From the high value of the 

 specific acti\'ity of the protein P in the 5 houis experiment it follows that the 

 protein phosphorus compounds present in the plasma were renewed even at a 

 higher rate than those of the phosphatides. This result suggests a great participa- 

 tion of the plasma phosphorus protein in the formation of the egg. To arrive at a 

 final conclusion as to the relation between the phosphorus protein compounds 

 of the plasma and those of the yolk and white is difficult because of the fact 

 that we lack simple methods of separation of the protein compounds. Vitellin, 

 for example, can only be isolated by a very tedious and lengthy process and the 

 isolation and separation of the blood protein phosphorus compounds are still 

 more difficult, partly because onl^• small quantities of these substances can be 

 secured in the ex})eriment. The fact that we have to base our conclusions on 

 the amount of phosphorus present in the residue, remaining after extraction 

 of the phosphatides and the acid soluble phosphorus compounds makes the result 

 obtained less trustworthy than those arrived at when investigating the phospha- 

 tides, for example. The high value for the protein phosphorus of the corpuscles 

 found by us, which may to some extent be due to an incomplete separation ot the 

 phosphatides and acid soluble P, is supported by the data obtained by Heller, 

 Paul and Thompson. They find for the total P present in the cells of laying 

 hens about 100 mgm %, but only about 40 mgm % for the sum of inorganic acid 

 soluble and lecithin P. The discrepancy suggests the presence of a further not 

 investigated P fraction, which might be protein P. In the case of the plasma 

 phosphorus the curves of Heller and his colleagues show the anomaly mentionetl 

 only to a smaller degree; the total phosphorus found by them is not very much 

 larger than the sum of the acid soluble and phosphatide P. 



