512 rX. CAROTENOIDS AND VITAMINS A 



for Egypt,607 300 I.U./g. for England/^^ 504 I.U./g. in Scotland,^''^ and 820 

 I.U./g. in Africa.««9 



b'. Cattle: Palmer and Eckles^^^'^^^ called attention to the fact that the 

 chief carotenoid in the tissues of cattle was /3-carotene. According to Par- 

 rish et al.^'^° and Goodwin, ^^^ from 92 to 97% of the total carotenoids in the 

 blood serum consist of carotenes. /3-Carotene is the main component of 

 the carotene fraction in the tissues of cows, but a number of investigators 

 have demonstrated the occurrence of a-carotene in butter.^^'^'-^^^-®^- 

 Gillam and Heilbron^^ reported that the principal carotenoids in butterfat 

 are a-carotene, /S-carotene, and lycopene. In the carotenol fraction, 

 which comprises only 5 to 8% of the total carotenoids, lutein is the chief 

 component, but cryptoxanthin has also been noted. ^^-^^^ The relative 

 amounts of carotene and of xanthophylls in milk and butter depend upon 

 the forage.^^*'^^^ 



Carotenoids, preferentially /3-carotene, accumulate in many tissues of 

 cattle and of other animals. They are present not only in blood, but also 

 in the liver,!^'^^'^^^ adrenal glands, '^'^"''1^ retina,*^"'^^""^- the pigment epithe- 

 lium and iris,^22 pituitary gland, ^^^'^^^ ovaries,^^^'^-'*'^'^ corpus lu- 

 teum, 151.246,259,623,624,626-630 ^^^^ corpus rubrum,^^^ placenta, i5i'6i6'«i9.623 ^^_ 



bilical cord blood, ^^^ colostrum,^^- bone-marrow,®'^ testes, '^^'^'^'^^^ thy- 



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613 F. W. Quackenbush, H. Steenbock, and W. H. Peterson, J. Am. Chem. Sac, 60, 

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"^ J. H. Mitchell and G. H. Wise, J. Dairy Set., 27, 189-196 (1944). 



618 B. C. Johnson, W. H. Peterson, and H. Steenbock, J. Dairy Sci., 24, 813-817 

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616 H. V. Euler and E. Klussmann, Biochem. Z., 256, 11-17 (1932). 



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618 O. Bailly and R. Netter, Compt. rend., 193, 961-963 (1931). 



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620 O. Brunner, E. Baroni, and W. Kleinau, Z. physiol. Chem., 236, 257-262 (1935). 



621 H. V. Euler and E. Adler, Arkiv Kemi, Mineral, GeoL, 11 B, No. 20, 1-6 (1933). 



622 H. J. Bielig and L. Busch, Z. physiol. Chzm., 280, 56-63 (1944). 



623 H. V. Euler, B. Zonek, and E. Klussmann, Arkiv Kemi, Mineral., GeoL, 11 B, No. 

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62" R. Kuhn and E. Lederer, Z. physiol. Chem., 200, 246-254 (1931). 



625 R. Netter, Bull. soc. chim. biol, 14, 1555-1559 (1932). 



626 J. L. W. Thudichum, Proc. Roy. Soc, 17, 253-256 (1869). 



627 G. Piccolo and A. Lieben, Giorn. sci. nat. econ. Palermo, 2, 258-272 (1866). 



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629 H. H. Escher, Z. physiol. Chem., 83, 198-211 (1913). 



630 R. Kuhn and W. Schlientz, Helv. Chim. Acta, 17, 7-8 (1934). 



631 G. Gaehtgens, Klin. Wochschr., 16, 894-895 (1937). 



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