808 XIII. ESSENTIAL FATTY ACinS 



total fatty acids. Schneider and co-workers'^^ state that linoleic acid 

 possesses a better (aii-ative action in pyridoxine deficiency than does lino- 

 lenic acid; it has also been fonnd that the effectiveness of several natural 

 fats in counteracting acrod3niia is in proportion to their linoleate content. 

 Corn oil was shown to be superior to linseed oil, while Salmon'^" found cod- 

 liver oil almost completely ineffective. Kichardson and associates'^^ 

 reported that both methyl arachidonate and linoleic acid resulted in good 

 growth, but that neither afforded permanent protection against the der- 

 matitis caused b}^ pyridoxine deficiency. These workers suggest that the 

 EFA do not replace pyridoxine but simply delay the onset of the skin 

 symptoms. 



The question naturall}^ arises as to whether or not the skin condition 

 resulting from EFA and from pyridoxine deficiency is the same. Medes 

 el al.^^^ emphasized the fact that an interrelation exists between the two 

 types of deficiency; however, their results might be interpreted to mean 

 that two different factors are involved. When the diet was lacking in 

 both factors, a relief from deficiency symptoms was obtained when either 

 ethyl linoleate or pyridoxine was administered. On the other hand, the 

 effectiveness of ethyl linoleate was less than it was when optimum doses 

 of pyridoxine were given. Best results were obtained when both of these 

 components were included in the diet simultaneously. 



The relationship between pyridoxine and oleic acid appears to be oppo- 

 site to that of pyridoxine and the EFA. Thus, Sarma et al.^^* observed 

 that the growth inhibition in rats caused by feeding diets deficient in pyri- 

 doxine or pyridoxal was accentuated when oleic acid was added to the diet. 

 However, the inhibitory action of oleate could be counteracted by the ad- 

 ministration of additional quantities of vitamin Be. Sinclair '^^ reviewed 

 the relationship between pyridoxine and the EFA. 



Fat is an effective agent in thyrotoxicosis. Thus, Greenberg and DeueP^® 

 observed that, on diets with a high cottonseed oil content, not only did rats 

 lose weight when thyroid powder was also given, but no mortality occurred. 

 In sharp contrast to this finding, the inclusion of thyroid hormone in a low- 



1" H. Schneider, H. Steenbock, and B. R. Platz, /. Biol. Chem., 132, 539-551 (1940). 

 1^2 L. R. Richardson, A. G. Hogan, and K. F. Itschner, Univ. Missouri Agr. Expt. 

 Sta., Research Bull. 333, 3-12 (1941); Chem. AbsL, 36, 2591 (1942). 



'" G. Medes, D. C. Keller, and A. Kurkjian, Arch. Biochem., 16, 19-29 (1947). 



164 P. S. Sarma, E. E. Snell, and C. A. Elvehjem, J. Nutrition, 33, 121-128 (1947). 



155 H. M. Sinclair, Essential Fatty Acids and Their Relation to Pyridoxine, in R. T. 

 Williams, Lipid Metabolism, Biochem. Soc. Symposia No. 9, 80-99, Cambridge Univ. 

 Press, 1952. 



156 S. M. Greenberg and H. J. Deuel, Jr., /. Nutrition, 42, 279-284 (1950). 



157 E. Keeser, Klin. Wochschr., 17, 1100-1103 (1938). 



