STORAGE OF CAROTENOIDS AND OF VITAMINS A 519 



require a small amount of vitamin A for normal functioning, and they \vill 

 remove this quantity from the blood and store it, to the exclusion of the 

 liver. Thus, Johnson and Baumann^^^ reported that, when rats were re- 

 ceiving minimum quantities of carotene or of vitamin A, more vitamin A 

 was accumulated in the kidneys than in the livers. When the dosage of 

 vitamin A was increased, the opposite condition obtained. They also re- 

 ported^®- a greater storage of vitamin A in the kidney than in the liver when 

 small doses of a-carotene, j8-carotene, neo-/?-carotene B and U were fed to 

 depleted rats. Eden and Moore®^^ confirmed the fact that, in young rats, 

 more vitamin A acetate was stored in the kidney than in the liver, except 

 when large doses were given. A greater storage of vitamin A occurred in 

 the kidneys of male rats than in those of female rats. 



(3) The Distribution of Carotenoids and of Vitamins A 

 Within the Cell 



Little information is available concerning the part of the cell in which 

 carotenoids are stored, except for the report of Berger.^®^ This investigator 

 made use of a specific reagent for the identification of carotenoids, which 

 allowed him to detect the presence of nuclei of various colors in the retinae 

 of mammals. Since the coloration disappeared in vitamin A deficiency, it 

 was concluded that the materials identified were carotenoids. It is also 

 postulated that vitamin A may constitute a portion of these nuclei. 



The site of deposition of vitamin A within the liver cell is a matter of con- 

 trovers3^ This may be due to the employment of different technics for the 

 separation of the fractions, and also to the fact that storage of vitamin A 

 may vsiry according to whether it is in the form of the ester of free al- 

 cohol. Joyet-La\'ergne*®^ reported that vitamin A was present in the mito- 

 chondria of liver cells. These findings were confirmed by Goerner^® 

 and by Colhns.^®^ However, Powell and Krause^®^ reported that, in the 

 liver cell of the normal rat, fraction "X" (the cj^toplasm remaining after 

 removal of the nuclei and mitochondria) contained the most vitamin A, 

 while the next highest concentration was in the mitochondria, and the 



^^ R. M. Johnson and C. A. Baumann, Federation Proc, 6, 265 (1947); /. Nutrition, 

 35, 703-715 (1948). 



«" R. M. Johnson and C. A. Baumann, Arch. Biochem., 14, 361-367 (1947). 



6«3 E. Eden and T. Moore, Biochem. J., 47, vi-vii (1950). 



•«* P. Berger, Compt. rend. soc. bioL, 144, 606-607 (1950). 



««5 P. Jovet-Lavergne, Bull. soc. chim. bioL, IS, 1041-1054 (1936). 



6«6 A. Goerner, J. Biol. Chem., 122, 529-538 (1938). 



«' F. D. ColUns, Biochem. J., 51, xxxviii (1952). 



^ L. T. Powell and R. F. Krause, Arch. Biochem. Biophys., 44, 102-106 (1953). 



