784 XIII. ESSENTIAL FATTY ACIDS 



agents in preventing the fat-deficiency syndromes was indicated by the 

 finding that a number of vegetable oils, such as corn, linseed, poppyseed, 

 and olive oils were likewise potent prophylactic agents/ Moreover, 

 glycerol, which is the other component of the active fraction (saponifiable) , 

 was proved to be completely ineffective as a curative compound.^ Re- 

 views of the nutritional significance of the essential fatty acids (hereafter 

 abbreviated as EFA) include that of Burr,^ one by Sherman,^ one by 

 Deuel and Greenberg,^ and another by Deuel alone.^ 



The polyunsaturated fatty acids were found by Klein and Johnson ^'i" to 

 be widely distributed in the cell. The proportion of the unsaturated 

 fatty acids (EFA) in mitochondria, microsomes, and the poorly sediment- 

 able layer of rat liver cells showed little fluctuation during growth and 

 maturation. However, there was an accumulation of trienoic acid in 

 senescent animals, which reached its highest concentration in the poorly 

 sedimentable layer of the oldest animals. In EFA deficiency, mito- 

 chondria, microsomes, and the poorly sedimentable layer lost dienoic, 

 tetraenoic, and pentaenoic acids at varying rates, while trienoic acid 

 increased steadily in all fractions. The most pronounced losses of poly- 

 unsaturated acids occurred in the microsomes. Fat-deficient animals 

 synthesized phospholipids at an increased rate (as determined by the rate 

 of uptake of radiophosphorus) , but the uptake in the acid-soluble organic P 

 fraction of the liver was decreased. These changes were found to occur 

 within six weeks on the fat-free diet, before any external symptoms of 

 EFA deficiency appeared. It is suggested that the changes accompany 

 the particulate lipid losses. Thus, the basic biochemical defect may 

 occur within a short period of exclusion of dietary fat. 



Earlier reviews of the significance of the essential fatty acids (EFA) 

 included those of Deuel, ^^ and of Holman and Greenberg.^^ 



2. Chemical Relations of Polyunsaturated Fatty Acids 



(/) Polyunsaturated Acids Having Biologic Importance 



The polyunsaturated fatty acids which were first recognized by Burr 

 and Burr* as possessing biopotency in curing or preventing the fat-de- 



" H. Sherman, Vitamins and Hormones, S, 55-08 (1950). 



^ H. J. Deuel, Jr., and S. M. Greenberg, Some Biochemirnl and N lUritional Aspects in 

 Fat Chemistry, Fortschr. Cheni. org. Nalursloffe, (>, l-8() (Ji)50). 

 « H. J. Deuel, Jr., Federation Proc, 14, G;?!)-G19 (1!)55). 

 " P. J). Klein and R. M. Johnson, Federation Proc, 12, 231 (1953). 



10 P. D. Klein and R. M. Johnson, Arch. Biochem. Biophys., 48, 380-385 (1954). 



11 H. J. Deuel, Jr., Progr. Chem. Fats and Other Lipids, 2, 99-192 (1954). 



^^ R. T. Holman and S. I. Greenberg, Arch. Biochem. Biophys., 49, 49-57 (1954). 



