Originally published in Biochem. J. 32, (1938) 



29. FORMATION OF PHOSPHATIDES IN LIVER 

 PERFUSION EXPERIMENTS 



L. A. Hahx and G. CH. Hevesy 



From the Institute of Theoretical Physics, University of Copenhagen 



About 2 hr after a meal containing fat, the fat content of the blood 

 begins to rise. This alimentary lipaemia is followed by lecithinaemia 

 [Reicher, 1911; Bloor, 1915], the phosphatide content of the blood 

 increasing more or less parallel with the fat content. A maximum is 

 reached after about 4 hr and after 8 hr the fat and phosphatide contents 

 of the blood are almost at the initial level. As to the origin of the phos- 

 phatides responsible for alimentary lipaemia the following possibilities 

 exist: 



(1) the phosphatides are synthesized in the intestinal mucosa and 

 resorbed into the blood; 



(2) they are synthesized in the blood; 



(3) they are mobilized under the influx of lipaemic blood from the 

 liver or other organs and possibly wholly or partly formed in the former 

 during the influx. 



To obtain further information on the above problem, oil together with 

 labelled (radioactive) sodium phosphate, were administered to a dog 

 [Hevesy anclLuNDSGAARD, 1937]. If the increase in the phosphatide con- 

 tent of the blood which amounted to 15 % after 4 hr. was due to phos- 

 phatides taken up from the intestine, the phosphatides extracted from 

 blood should have shown a marked radioactivity. The latter was, how- 

 ever, much smaller than to be expected on this assumption. It follows that 

 while phosphatides are synthesized in the intestinal mucosa [Artom 

 et al., 1937; Sinclair and »Smith, 1937] and some do enter the circulation 

 from the bowels [Himmerich, 1934; Sxillmann and Wilbrandt. 

 1934; Freeman and Joy, 1935] the bulk of the phosphatides which 

 are responsible for the alimentary lipaemia must originate from outside 

 the intestinal tract. We next tested the possibility that the additional 

 phosphatides are formed in the lipaemic blood [Hahn and Hevesy. 

 1938]. A few ml. of dog blood were shaken with labelled sodium phos- 

 phate under the usual precautions for 4.5 hr. The phosphatides ex- 

 tracted after the experiment were only slightly radioactive, the labelled 



