798 XIII. ESSENTIAL PATTY ACIDS 



observed by Cheng^^ that triolein affords no protection against x-irradia- 

 tion injury. Alfin-Slater et al.^^-^^ found the administration of methyl 

 oleate ineffective in counteracting the abnormal cholesterol accumulation 

 in the liver which occurs in fat deficiency. These results leave no doubt 

 that oleic acid is entirely ineffective in preventing or curing the deficiency 

 brought about by the exclusion of EFA from the diet. 



In addition to the negative response to oleic acid, Thomasson^^ reported 

 that the following closely related monoethenoid acids likewise lack any 

 biopotency: 11-octadecenoic acid; 12-octadecenoic acid; 13-docosenoic 

 acid (erucic); and 12-hydroxy-9-octadecenoic acid (ricinoleic). Turpeinen'^ 

 also noted that 12-octadecenoic acid, erucic, and ricinoleic acids, as well as 

 chaulmoogric acid, are without biologic activity. Elaidic acid, the trans- 

 isomer of oleic acid, has likewise been reported to be without curative effect 

 in fat deficiency. It is thus obvious that none of the monoethenoid acids 

 affords protection from fat deficiency. 



{4) The Biopotency of Linolenic Acid vs. Linoleic Acid 



Burr and co-workers'' stated that linoleic and linolenic acids possess 

 about equal potency in protecting against the fat-deficiency syndrome. 

 However, a number of workers have disagreed with these original observa- 

 tions. For example, Martin^^ obtained negative results with the triethe- 

 noid acid, and Hume and collaborators'^ stated that linolenic acid has only 

 one-sixth of the biopotency of linoleic acid. On the other hand, Tange'-'' 

 noted that these acids have the same biologic activity. More recently, 

 Greenberg et al.^^ reported that linolenic acid, when given alone, was prac- 

 tically without activity to restore growth in fat-deficient rats. However, 

 when the triethenoid a(dd was administered together with linoleic acid, the 

 effect of Ihiolenic acid appeared to be equivalent to that of linoleic acid, 

 and the effects of the two acids were additive. This was confirmed by 

 Deuel and co-M'orkers.^^ Another interpretation is that linolenate "pro- 

 tects" linoleate during transport and storage, thus making more linoleate 

 available for metabolic purposes. 



Thomasson,'^ using his bioassay technic for the EFA, reported a new 



'1 A. L. S. Cheng, Personal communication to the author (H. J. D.), 1954. 



" R. B. Alfin-Skter, L. Aftergood, A. F. Wells, and H. J. Deuel, Jr., Federation Proc, 

 13, 174(1954). 



93 R. B. Alfin-Slater, L. Aftergood, A. F. Wells, and H. J. Deuel, Jr., Arch. Biochem. 

 Biophys., 52, 180-185 (1954). 



9" G. J. Martin, ./. Nutrition, 17, 127-141 (1939). 



95 H. J. Deuel, Jr., C. R. Martin, and R. B. Alfin-Slater, J. Nutrition, 57, 297-302 

 (1955). 



