554 IX. CAROTENOIDS AND VITAMINS A 



(4) The Excretion of Carotenoids and 

 of Vitamin A in the Urine 



The kidney plays an important role in the metabolism of vitamin A. It 

 has been shown to be an important organ in the storage of vitamin A, and 

 exhibits a higher priority for this component than does the liver when the 

 supplies of vitamin A are limited. 



Vitamin A has been found in the urine of human patients suffering from 

 cancer, renal tuberculosis, and severe general infections, and especially in 

 conditions involving renal and hepatic dysfunction, for example, in gono- 

 toxic icterus, obstructive jaundice, chronic nephritis and other nephroses, 

 cirrhosis of the liver, cholelithiasis,'^"'^^^ and also in lobar pneumonia.^^^ 

 The storage of vitamin A in the kidney is reduced in the case of patients 

 with chronic nephritis ;^^^'''^* the level of vitamin A in the blood is con- 

 comitantly increased. ^^'^^ According to Baumann et al.,""^^ following the 

 injection of dibenzanthracene, the kidney vitamin A is maintained at higher 

 levels than is that in the liver. 



The absence of vitamin A in the diet causes an injury to the kidney. 

 Thus, Herrin and Nicholes^^^ reported that the urea clearance of vitamin 

 A-deficient dogs was well below normal, due to changes in the glomerular 

 filtration. However, Kaiser, Francis, and Kagan^^^ were unable to dem- 

 onstrate any differences in serum or liver vitamin A levels in male white 

 rats which were subjected to bilateral nephrectomy, as compared with con- 

 trol animals. This would indicate that the normal mature kidney plays 

 no significant role in vitamin A metabolism in such short-term experi- 

 ments in the rat. 



Hymans, van den Bergh, and Snapper^*^ believed that lutein was ex- 

 creted in instances in which the blood lipochrome level was high. How- 

 ever, in more recent studies by Lawrie, Moore, and Rajagopal,^" no evi- 

 dence of carotenuria was found. Moreover, no urinary vitamin A was 

 recorded in physiologic conditions such as pregnancy, or in any pathologic 

 conditions with the exception of chronic nephritis or pneumonia. In the 

 latter condition, vitamin A was excreted in tiuite large amounts, apparently 

 combined with a protein. As much as 3000 I.U. of vitamin A per twenty- 



852 R. Boiler, O. Brunner, and E. Brodaty, Wien. Arch. inn. Med., 31, 1-22 (1937): 

 Chem. Abst., 31, 7988 (1937). 



8" R. Boiler and O. Brunner, Klin. Wochschr., 16, 861-862 (1937). 



85^ R. C. Herrin and H. J. Nicholes, Am. J. Physiol, 125, 786-801 (1939). 



8" E. Kaiser, Y. F. Francis, and B. M. Kagan, Proc. Soc. Exptl. Biol. Med., 85, 

 457-458(1954). 



856 A. A. Hymans, H. van den Bergh, and J. Snapper, Dent. Arch. klin. Med., 110, 

 540-561 (1913"). 



8" N. R. Lawi-ie, T. Moore, and K. R. Rajagopal, Biochem. J., 35, 825-836 (1941). 



