STORAGE OF CAROTENOIDS AND OF VITAMINS A 515 



In the group of higher vertebrates, the animals which do not accumulate 

 carotenoids in the liver and other tissues are far more common than are 

 those which store carotenoids. According to Jensen and With,!^^ ^j^g ^^^g^ 

 majority of animals examined contained only traces, or no carotenoids 

 whatsoever. The failure to accumulate these pigments has been attrib- 

 uted to the very efficient conversion of the provitamins A in the wall of 

 the intestine to vitamin A. It is not known what the fate of the xantho- 

 phylls may be, but it is believed that they may be broken down in a manner 

 resembling that of the carotenes. Goodwin^-^ obtained evidence that lu- 

 tein (xanthophyll) is absorbed by the rat; as he was able to recover small 

 amounts of the mono-esters and di-esters from the intestinal wall. No 

 trace of the absorbed pigment could be detected in other tissues. 



The blood and liver of the animals which belong in this category contain 

 no carotenoid, or only traces. These include goats, ^^^■^''''■^''^ g^^Q2n.2^4M6M^ 

 rats,^^'-^^'"-'^^^ rabbits, 13^ '"^ as assumed ^^^ on the basis of indirect evidence 

 furnished by the staining experiments of Connor,^^^ hares/^" and guinea 

 pigs.^" Sheep apparently are on the border Hne, since their livers contain 

 only traces of carotenoids.-^^ Ganguly et alr^"^ were unable to demonstrate 

 the presence of carotenes or of carotenols in the blood or ovaries of a sheep 

 presumably from the Southern California area. Only traces appeared in 

 the liver. According to Coombes et al.,^^^ foxes might also be considered 

 to be in a borderline group, since they have a low plasma carotenoid con- 

 tent, and no carotenoids are stored in the liver. Even after the feeding of 

 high doses of ,S-carotene, no accumulation occurs in the blood of rats,"^--^- 

 pjgg^272,273 guinea pigs,'" or rabbits.'^^ Only small amounts of carotene 

 were found in the blood of sheep following the administration of massive 

 doses. ®^2 Zechmeister and Tuzson^" reported that less than 0.1 mg./kg. 

 of carotenol appeared in the fat of pigs which had been fed on a diet rich in 

 these pigments for an extended period. The liver was found to contain 

 only one-fifth to one-tenth of the above amount. 



"* B. N. Banerjee and N. C. Datta, Agr. Livestock, India, 8, 563-567 (1938); Chefu. 

 Abst.,33, 2564(1939). 



6« V. R. Smith, R. P. Niedermeier, and L. A. Schultz, /. Animal Sci., 7, 544 (1948). 



6« L. A. Palmer, Am. J. Physiol., 87, 553-557 (1929). 



6" L. Zechmeister and P. Tuzson, Z. physiol. Chem., 239, 147-148 (1936). 



«« R. L. Shub, Akushsrstvo i. GinekoL, 1940, No. 10, 6-8; Chern. Abst., 37, 1170-1171 

 (1943). 



6" C. L. Connor, Am. J. Pathol., 4, 235-244 (1928). 



«o R. A. Morton and G. D. Rosen, 1949, unpubhshed data cited by T. W. Goodv\'in, 

 The Comparative Biochemistry of Carotenoids, Chem. Pub. Co., New York, 1954, p. 247. 



«i A. I. Coombes, G. L. Ott, and W. Wisnickv, North Am. Veterinarian, 21, 601-606 

 (1940). 



6" E. R. Barrick, F. N. Andrews, and J. F. Bullard, J. Animal Sci., 7, 539 (1948). 



