518 IX. CAROTENOIDS AND VITAMINS A 



workers^^^ also reported that, although the liver is usually the storehouse 

 for vitamin A, in the case of the hake {Merluccius merluccius) the intestine 

 carries out this function. Lovern, Morton, and Ireland^^ likewise ob- 

 served that the \atamin A concentration in the oil from the intestines of the 

 sturgeon {Acipenser sturio) was ten times as high as it was in the liver oil. 

 Since this is a freshwater fish, part of the vitamin A was in the form of vita- 

 min A2. It was found that the ratio of vitamin A to vitamin A2 was much 

 higher in the intestine than in the liver. It is concluded that vitamin A and 

 vitamin A2 do not replace each other with equal facility in all functions. 

 Lovern et al.^^ noted that sea birds had a higher proportion of vitamin A in 

 the intestines than did animals such as the rabbit. In the blue-gray Ameri- 

 can and European herring gull (Larus argentatus smithsonianus) and the 

 great red-brown skua gull or bonxie (Megalestris catarrhactes) , the liver con- 

 tained more vitamin A than did the intestine. No vitamin A2 was found. 

 In the white gannet or Solan goose {Sula hassana) the lungs contained rela- 

 tively large amounts of vitamin A, and the li\'er and intestines very little. 

 On the other hand, a high proportion of the vitamin A was stored in the 

 body fat of the eel (Anguilla vulgaris). 



The main sites in which \'itamin A is stored in the vertebrates are the 

 liver and eyes. Although \dtamin A is ordinarily not present in many of 

 the invertebrates, when it does occur, it is almost entirely concentrated in 

 the eyes. Thus it was found that practically the entire vitamin A content 

 of the whole organism in the northern euphausiid shrimps (Meganycti- 

 phanes norvegica and Thysanoessa raschii) is present in the eyes.^^^ A large 

 proportion of the total astaxanthin in these species is present in the eyes. 

 Although as high an actual amount of vitamin A is to be found in the eyes 

 of the vertebrates, it constitutes only an insignificant proportion of the total 

 vitamin A stored, because a much larger total amount of vitamin A is 

 present in the higher animals than in lower forms. 



The liver constitutes the main storage site in the birds and in the higher 

 vertebrates, including the rat^"~^^^ and pig.^®° Smaller concentrations are 

 found in the kidney, the lungs, the adrenals, the adipose tissues and in the 

 blood plasma. While the hver is the principal organ in which the excess 

 vitamin A is removed from the blood for storage, apparently the kidneys 



"^ R. Grangaud, R. Massonet, and H. Larroque, Compt. rend. soc. hiol., 143, 1181- 

 1183 (1949). 



6»« J. A. Lovern, R. A. Morton, and J. Ireland, Biochem. J., 83, 325-329 (1939). 



6" A. B. McCoord and E. M. Luce-Clausen, /. Nutrition, 7, 557-572 (1934). 



658 H. C. Sherman and L. C. Boynton, /. Am. Chem. Soc, 47, 1646-1653 (1925). 



6" C. A. Baumann, B. M. Riising, and H. Steenbock, /. Biol. Chem., 107, 705-715 

 (1934). 



6«« T. B. Osborne and L. B. Mendel, J. Biol. Chem,., 34, 17-27 (1918). 



