OCCURRENCE OF THE VITAMINS A 677 



Other visceral organs of some fishes have been found to be richer sources 

 of vitamin A than is the Hver.^'"''-' In the case of the hahbut, large de- 

 posits of vitamin A, almost exclusively in the form of the ester, occur in the 

 intestine, where they are localized in the mucosa and in particular in the 

 tunica propria.^" ~^^ 



(2) Vitamin A in Animals Other Than Fishes 



The liver is also the chief site of storage of vitamin A in animals other 

 than fishes. Jensen and With®^ demonstrated the presence of this fat- 

 soluble vitamin in two species of reptiles, 36 species of birds, and 22 species 

 of mammals, including man. The concentration is usually highest in fish 

 livers, next in the livers of birds and reptiles, and lowest in the livers of 

 mammals. In the last group, the concentration in the liver of guinea pigs 

 has been found to be unusually low.^'* Large amounts, approaching that 

 present in the fish livers, were reported in one mammal, the great blue 

 whale (Balaenoptera musculus)}^ 



Strangely enough, on the basis of a survey of the distribution of vitamin 

 A, Karrer, von Euler, and Schopp*^" reported that the livers of the following 

 mammals were devoid of vitamin A: Bengal tiger {Felis tigris), adult and 

 young male lion {Felis leo), crab-eating raccoon (Procyon cancrivorus) , har- 

 bor seal {Phoca vitulina), cormorant {Phalacrocorax carho), salamander 

 (a,xo\ot\)(Amby stoma spp.), and one species of reptile, the leopard adder 

 {Coluber quadrilineatus) . It is not known whether the absence of vitamin 

 A is the result of the previous diet or whether vitamin A is readily destroyed 

 or is not stored in these animals. In such cases, one might suspect that it 

 is not a necessary nutrient. Other species which apparently do not require 

 vitamin A are the cockroach or Croton bug, Blattella {Phyllodromia) 

 germanica,^" and the clothes moth (Tineola hisseliella) }^ Bowers and Mc- 

 Cay^^ were able to raise the cockroach to maturity on a vitamin-A-free diet. 

 The fact that vitamin A was not synthesized de novo is indicated by its ab- 



'" J. A. Lovern, J. R. Edisbury, and R. A. Morton, Nature, I40, 276 (1937). 



58 J. R. Edisbury, J. A. Lovern, and R. A. Morton, Biochem. J., 31, 416-423 (1937). 



*' J. R. Edisburv, R. A. Morton, G. W. Simpkins, and J. A. Lovern, Biochem. J., 32, 

 118-140(1938). 



«" J. A. Lovern, T. H. Mead, and R. A. Morton, Chemistnj & Industry, 58, 147 (1939). 



«i J. A. Lovern and R. A. Morton, Chemistry & Industry, 58, 147 (1939). 



«2 J. A. Lovern and R. A. Morton, Biochem. J., 33, 330-337 (1939). 



«3 J. Glover and R. A. Morton, Biochem. J., 42, Ixiii-lxiv (1948). 



" H. B. Jensen and T. K. With, Biochem. J., 33, 1771-1786 (1939). 



^5 S. Schmidt-Nielsen and S. Schmidt-Nielsen, Kgl. NorsJce Videnslcab. Selskabs Forh., 

 3, No. 46, 177-180 (1930); Chem. Ahst., 26, 1642 (1932). 



«6 P. Karrer, H. v. Euler, and K. Schopp, Helv. Chim. Acta, 15, 493-495 (1932). 



^ C. M. McCav, Physiol. ZooL, 11, 89-103 (1938). 



68 M. F. Crowell and C. M. McCay, Physiol. ZooL, 10, 368-372 (1937). 



«« R. E. Bowers and C. M. McCay, Science, 92, 291 (1940). 



