CONCLUSIONS 833 



as compared with vvell-noiirislied individuals. However, the dieiioic, 

 tetraenoic, and hexaenoic acid levels were distinctly lower, and the propor- 

 tion of trienoic acid was higher, in the poorly nourished group as compared 

 with the well-nourished children. The following figures were reported for 

 sixty well-nourished and thirty -four malnourished children, respectively: 

 total fatty acids, 301 and 278 mg. %; dienoic acids, 30.3% and 12.0%; 

 trienoic acids, 1.5% and 2.4%; tetraenoic acids, 10.2% and 7.0%; and 

 hexaenoic acids, 4.2% and 1.8%. 



The polyunsaturated fatty acids have a wide distribution in tissues; 

 however, because of the relatively difficult procedures for isolation, and 

 because of the low concentration, there is little information in this field. 

 Arachidonic acid, either as its polybromide or as the pure acid, has been 

 isolated from a number of the tissues. These include the following: 

 liver lecithin, -2^ brain phospholipids,^" corpus luteum,^^^ egg yolk,-^ 

 pig liver, 2^" beef adrenal phosphatides obtained by debromination of methyl 

 octabromoarachidate by Ault and Bro\vn,-^i and by the use of chromato- 

 graphy by White and Brown-^^ and by Herb et al^^^'^^ 



Holman and Greenberg^"* investigated the proportion of tetraenoic, pen- 

 taenoic, and hexaenoic acids in several non-adipose tissues from lambs, 

 hogs, and beef cattle. The highest proportion of arachidonic acid was 

 found in the testes and ovaries. Of the fatty acids of lamb testes, for 

 example, 15.6% is hexaenoic acid and 10.3% is arachidonic acid. From 

 the standpoint of isolation, the most practical sources of hexaenoic acid 

 were beef testes lipid and hog brain lipid, while arachidonic acid could best 

 be prepared from hog liver lipid. 



9. Conclusions 



The essential fatty acids, linoleic, linolenic, and arachidonic acids, have 

 been found to mediate a number of reactions in the animal body. Thus, 

 not only are they important in growth and in the nutrition of the skin, as 

 has been recognized since the discovery of their indispensability, but they 

 are now recognized as specific agents in protecting the animal against x- 

 irradiation injury. They also maintain capillary pressure in the subcutane- 



22« P. A. Levene and H. S. Simms, J. Biol. Chem., 51, 285-294 (1922). 



227 P. A. Levene and I. P. Rolf, /. Biol. Chem., 54, 91-98, 99-100 (1922). 



228 G. F. Cartland and M. C. Hart, ./. Biol. Chem., 66, 619-637 (1925). 



229 P. A. Levene and I. P. Rolf, /. Biol. Chem., 51, 507-513 (1922). 



230 J. B. Brown, /. Biol. Chem., 80, 455-460 (1928). 



2" W. A. Ault and J. B. Brown, J. Biol. Chem., 107, 607-614 (1934). 



•"2 M. F. White and J. B. Brown, J. Am. Chem. Soc, 70, 4269-4270 (1948). 



