310 ASCORBIC ACID 



weight response tests with ascorbic acid in daily doses ranging from 0.2 to 

 0.8 mg. per animal. 



The relation of ascorbic acid to growth of specific organs, such as the 

 teeth and adrenals, is discussed in the section on requirements (p. 380). 



There is little evidence of a direct relation between ascorbic acid and 

 growth of cells in animal tissues. Glick and Biskind^^" observed that the 

 size and vitamin C content of the cells of the adrenal cortex increased regu- 

 larly from the fetal to the adult stage of the animal. Studies of localization 

 of the vitamin in cells of animal tissues reveal a distribution similar to that 

 observed in plant cells, namely that it is found in cytoplasm, apparently 

 often at the surface of the cells but none in the nucleus. 



3. Distribution in Organs and Tissues 



Ascorbic acid is probably present in all tissues of higher animals, at least 

 during the developmental stages. Under normal conditions of nutrition 

 tissues of young, rapidly growing animals tend to have a higher content 

 than those of older animals fed the same diet.--^ The content tends to be 

 highest in glandular tissues and lowest in fat, skin, connective tissue in 

 general, and muscles. The adrenals, hypophysis,^- and young thymus have 

 a high content. Somewhat lower concentrations are found in spleen, pan- 

 creas, liver, testes, ovaries, brain, thyroid, and submaxillaries.^^'^ Table IX 

 shows the average values found in guinea pig organs as determined by sev- 

 eral investigators."^ • 2-3-226 ^ fairly high content of the vitamin has also been 

 shown to be present in the walls of the intestinal tract.^^''"^^^ Zilva^^^ showed 

 that in guinea pigs fed a diet containing ascorbic acid the vitamin is selec- 

 tively absorbed by the intestinal walls. An accumulation in the intestinal 

 wall is also produced when the vitamin is injected directly into the blood 

 stream. With as much as 100 mg. injected the concentration was approxi- 

 mately the same as with ingestion of the normal diet containing the vitamin. 

 With 70 mg. injected the concentration in the intestinal wall was only half 

 as much. It is quite probable that with the very high injected dose the vi- 

 tamin was being excreted into the lumen of the intestine.-®' -^^ Ludany 



"» D. Glick and G. R. Biskind, J. Biol. Chcm. 115, 551 (1936). 

 2" O. A. Bessey and C. G. King, J. Biol. Chem. 103, 687 (1933). 



222 H. A. Salhanick, L. G. Zarrow, and M. X. Zarrow, Endocrinology 45, 314 (1949). 



223 J. H. Roe, J. M. Hall, and H. M. Dyer, Am. J. Digest. Diseases 8, 261 (1941). 



224 C. A. Kuether, I. R. Telford, and J. H. Roe, J. Nutrition 28, 347 (1944). 



225 J. R. Penney, S. S. Zilva, Biochem. J. 40, 695 (1946). 



226 M. E. Reid, /. Nutrition 42, 347 (1950). 



22' E. Harde and J. Wolff, Compt. rend. soc. biol. 116, 288 (1934). 



228 F. G. Hopkins, J. Soc. Chem. Ind. 53, 874 (1934). 



229 S. S. Zilva, Biochem. J. 29, 100 (1935). 



230 M. E. Reid, Proc. Soc. Exptl. Biol. Med. 68, 403 (1948). 



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