RATE OF PENETRATION OF PHOSPHATIDES THROtOH THE fAl'IM.AHV \\.\U. 269 



phosphatides between equal volumes of the plasma and the extracellular 

 fluid of the organs in question is stated on the assumption that the 

 labelled phosphatides are solely to be found in the interspaces of the 

 organ in question. The conclusion to be drawn from the figures of this 

 column are discussed on page 270. 



Tabi.k tt. — Labkm.ki) Phosphatides Found in the Organs f>K Kabbit B aftkk 



THK Lapse of 4 Hours 



Organ 



Weight 



rercentago of tlie lal)ellfU 



phosphatides injected into 



the vein, present in 



the blood- 

 tree organ 



1 (■<!. oxtra- 



oeUular 



fluid' 



Distribution eoel- 

 ficient' of labelled 

 phosphatides between 

 equal volumes of 

 extracellular water 

 and plasma water 



Liver 



Kidneys 



Muscles 



Heart 



Spleen 



Small intestine mucosa 



Lungs 



Hrain 



Plasma 



28.9 

 0.88 

 2.5 

 0.21 

 0.06 

 1.1 

 1.0 

 0.05 



2.17 



0.19 



0.018 



(1.12 



O.K) 



0.065 



0.22 



0.022 



9.8 



0.85 



0.082 



0.54 



0.72 



0.29 



1.0 



0.10 



0.22 



• Calculated on the assumption that no penetration of labelled phosphatides into tlie cells took place 



In another experiment, only the labelled phosphatide content of 

 liver and muscles were determined. The liver, weighing 85 gm, contained 

 38 per cent of the labelled phosphatides injected after the lapse of 4 

 hours, while in the blood-free muscles, weighing 1060 gm, 2.7 per cent 

 of the labelled phosphatides administered were present. 



The figures given above relate to the labelled phosphatide content 

 of organs of rabbits killed by bleeding. While such organs have only 

 a comparatively small blood content, this cannot be entirely disregarded. 

 Some of the labelled phosphatides present in the organs will be due to 

 their blood content. In the muscles of the rabbit we found, by making 

 use of the method of Eichelberger and Hastings (1937), that the 

 blood content amounted to 0.5 per cent of the organs' weight. In the 

 experiment described above, in which the weight of the muscles was 

 1060 gm and the total plasma of the rabbit amounted to 97 cc, the 

 blood present in the muscles contained 1.0 per cent of the labelled phos- 

 phatides injected. In the case of the liver, the corresponding figure 

 works out to be less than 1 per cent; in the case of the other organs 

 the correction is insignificant. 



