282 



ESSENTIAL FATTY ACIDS 



lustrated in Fig. 3, for the fatty acids of heart and kidney, in which these 

 changes are most pronounced. 



The metabohc conversions have been studied using some unnatural 

 isomers of the essential fatty acids. ^^ The responses to the natural and 



WEIGHT GAIN 



100 



q/tlAT 



2 

 50 r^ 



O O 

 2: 2 



t 



FATTY ACIDS 

 q/RAT 



10 



U5 



TETRAENOIC ACID 

 200 mg /rot 



100 



2 



iH 



!i 



Fig. 4. Weight response, total fatty acid synthesis, tetraenoic acid synthesis, and 

 hexaenoic acid synthesis as the result of supplementation of fat-deficient rats with 

 isomeric essential fatty acids. ^"^ ^' 



unnatural isomers are summarized in Fig. 4. Only the natural (cis) isomers 

 promote normal growth, but elaidolinolenic acid (trans , trans ,trans-\mo- 

 lenic) promotes a suboptimal weight gain. Total fatty acid synthesis is 

 stimulated by the natural essential fatty acids and by /mns-linolenic acid. 

 Tetraenoic acid deposition is stimulated only by the natural essential acids, 

 and hexaenoic acid deposition by the natural isomers plus /ra/is-linolenate. 



11 R. T. Holman, Proc. Soc. Exptl. Biol. Med. 76, 100 (1951). 



