DEFICIENCY OF THE PHOSPHOLIPIDS 249 



4. The Effect of Deficiency of the Phospholipids 



(1) The Effect of Phospholipid Deficiency in General 



Phospholipids play so many varied roles in metabolism that their de- 

 ficiency in the diet may cause many abnormalities, and may actually result 

 in death. However, the body is able to synthesize phospholipids from the 

 A'arious building stones to such a great extent that it is only when there is a 

 prolonged deficiency of some of the compounds incapable of synthesis in 

 the animal body that a deficiency in phospholipid itself occurs. Glycerol 

 and the saturated and monoethenoid acids are always readily available 

 for phospholipid s^mthesis, as are also phosphate and ethanolamine. The 

 only substances, shortages of which may become critical, since they cannot 

 be synthesized in the body and must be furnished in the diet, are the essen- 

 tial fatty acids, choline (mider certain circumstances), and sphingomyelin. 



When facilities for the synthesis of a sufficient amount of phospholipids 

 are lacking, the most obvious abnormalities which occur involve the trans- 

 portation of the fats. For example, fatty livers develop. In extreme cases 

 of phospholipid deficiency, insuflftcient amounts of these compounds are 

 present to serve as cell membranes, with the result that serious difficulties 

 arise, which may result in hematuria and even in death. In addition to the 

 role of phospholipids in the transport and storage of fats, which was de- 

 scribed in The Lipids, Volume II, in the section on fatty livers, pages 633- 

 697, one of the phospholipid components of thromboplastin has an added 

 function, in that it activates the conversion of prothrombin to thrombin in 

 the process of blood coagulation. A deficiency of this component would 

 interfere with the conversion. The phospholipids assure permeability of 

 the cellular membranes as far as ions are concerned, and also appear to play 

 a role in the transport of metals, accordmg to Leulier et al.^"^ These workers 

 found that brain lipids contain about 0.5% of sodium and potassium. In 

 the absence of phospholipids, obviously this function is disturbed. Further- 

 more, the phospholipids appear to be the factor in some animal sera which 

 is capable of inactivating certain types of virus. This was found to be 

 true of the lecithin-like and cephalin-like fractions of serum lipids in psit- 

 tacosis (Bacterium psittacosis).^^ Elson^'* showed that certain phospholipids 

 ha\'e both an inhibitory and a "killing" action on the effect of propamidine 

 (4:4'-diamidino-l:3-diphenoxypropane) on disease organisms; the sub- 



'^ A. Leulier, B. Drevon, and A. Bernard, Compt. rend. soc. biol., 1^2, 1131-1134 

 (1948). 



" J. P. Utz, Proc. Soc. Exptl. Biol. Med., 69, 186-189 (1948). 

 9* W. O. Elson, J. Biol. Chem., 154, 717-718 (1944). 



