460 V. BLOOD LIPIDS 



obstructive ligation of the common bile duct could not be prevented by 

 prior castration, adrenalectomy, viscerectomy, or ligation of the thoracic 

 duct. However, total or partial hepatectomy prevented the development 

 of hypercholesterolemia. Moreover, no increase in cholesterol could be 

 produced in the partially hepatectomized animal by intravenous infusion 

 of choline, inositol, lecithin, or unchanged bile. It was concluded that the 

 liver itself discharged the excess cholesterol into the blood stream following 

 ligation of the bile duct, although it was not assumed that the liver is 

 necessarily concerned with the formation of the cholesterol in the plasma 

 of normal intact rats. 



Lipid phosphorus increases somewhat more than does cholesterol, in 

 biliary obstruction, with a resultant increase in the lipid phosphorus: 

 cholesterol ratio. 215 On the other hand, the neutral fat fraction is some- 

 what increased at the height of the obstruction, although this increase is 

 considerably less than that of the other fractions. 



Friedman and Byers 679 also found an increase of lecithin as well as of 

 bile acids in the plasma, following biliary obstruction. These investi- 

 gators 680 were of the opinion that the hypercholesterolemia which occurs 

 after the occlusion of the bile duct is due to the retention of some sub- 

 stance other than cholesterol, which, in turn, induces an increased level 

 of blood cholesterol. Since the administration of lecithin was without an 

 effect on hypercholesterolemia, it is suggested that the bile acids are re- 

 sponsible for this condition. 679 



Turner et al. 67i reported that, in 16 of 21 cases of obstructive jaundice 

 due to neoplasm, the activity of the cholesterol-esterifying enzyme in human 

 serum was decreased. This is in line with the report of Albrink and co- 

 workers 677 that the ratio of free to total cholesterol rises markedly in ob- 

 structive jaundice. The total cholesterol was lowest where the element 

 of parenchymal damage was greatest, and highest when the element of 

 obstruction was highest. 677 The level of phospholipids was found to bear 

 a close relationship to that of the free cholesterol, even when the ratio of 

 free cholesterol : total cholesterol was considerably distorted. 677 It is sug- 

 gested that this constancy may reflect a basic process in the liver whereby 

 fatty acids are apportioned to the phospholipids and to cholesterol. Byers 

 and collaborators 681 likewise reported that, after simple ligation of the bile 

 duct in rats, the free cholesterol of the plasma was rapidly increased, 

 while a much slower and less rapid rise in the esterified cholesterol level 



679 M. Friedman and S. O. Byers, Am. J. Physiol, 168, 292-296 (1952). 



68° M. Friedman and S. O. Byers, J. Exptl. Med., 95, 19-24 (1952). 



681 S. O. Bvers, M. Friedman, and F. Michaelis, J. Biol. Chem., 184, 71-75 (1950). 



