VIII. EFFK(n'S OF DEFICIENCY IN ANIMALS 331 



May iiiid coworkers''*" tluit megaloblastic anemia in monkeys, associated 

 with a deficiency of ascorbic acid, could be cured promptly either by 

 very small amounts of folinic acid or ascorbic acid suggests such a relation- 

 ship. 



(9) Vitamin B\>. Dietrich ct al}'''-' found that addition of both ascorbic 

 acid and vitamin B12 to chicks on a semipurified diet resulted in greater 

 growth than with either one alone. As previously mentioned, ascorbic acid 

 has been shown to have a growth-promoting effect on L. leichmannii, an 

 organism which requires vitamin 1^12 also. On the other hand, reports have 

 been made of a destructive action of ascorbic acid on vitamin B12 in solu- 

 tion. Gakenheimer and Feller^*^ found that more than 50% decomposition 

 of vitamin B]2 occurred in solutions containing ascorbic acid within 24 hours 

 when stored at 28 to 30°. Lang and Chow^^^ also observed that ascorbic 

 acid caused a destruction of vitamin B12 on standing, the rate of change 

 varying wdth pH. 



(10) Summary of Vitamin Interrelations, (a) Effect of Ascorbic Acid on 

 Other Vitamins. Ascorbic acid appears to influence the blood and tissue 

 levels of vitamin A. It protects tocopherol against oxidation in the tissues, 

 has a sparing or functional effect on members of the B complex, and may 

 possibly influence the synthesis of some of them. 



(b) Effect of Other Vitamins on Ascorbic Acid. Vitamin A appears to 

 have a stimulatory effect on the synthesis of vitamin C in the rat; in ex- 

 cessive amounts it may lessen the capacity of the tissues to retain vitamin 

 C. Vitamin E has a protective effect on ascorbic acid. Thiamine, riboflavin, 

 and pantothenic acid have a stimulatory effect on ascorbic acid synthesis 

 in rats, and thiamine and riboflavin may affect fixation of the vitamin in 

 the tissues of guinea pigs. 



5. Enzymes Affected by Ascorbic Acid Deficiency 



Ascorbic acid has marked effects on some types of enzymes. The systems 

 which showed a marked drop in activity in scurvy are succinic dehy- 

 drogenase,^*** alkaline phosphatase in bones^'*' ^^^ and skin, phosphorylase, 

 and the enzyme controlling tyrosine oxidation.-"^''' " Enzymes which have 

 been reported to become overactive in the deficiency are adenosine triphos- 



=!" C. D. May, E. N. Nelson, R. J. Salmon, C. U. Lowe, R. I. Licnke, and D. Sund- 



berg, Bull. Univ. Minn. Hosp. 21, 208 (1950). 

 '88 W. C. Gakenheimer and B. A. Feller, /. Am. Pharm. Assoc. Sci. Ed. 38, 660 (1949). 

 3" C. A. Lang and B. F. Chow, Federation Proc. 9, 193 (1950). 



388 C. J. Harrer and C. G. King, J. Biol. Chem. 138, 111 (1941). 



389 G. H. Bourne, Quart. J. Expll. Physiol. 32, 1 (1943). 



