330 ASCORBIC ACID 



deficiency symptoms and permitted normal growth and development. More 

 recent results from the same laboratory"^ suggest that this is a nonspecific 

 effect. 



(8) Pieroylglutamic Acid. Silverman and Mackler"^ found that pteroyl- 

 glutamic acid (PGA) has no antiscorbutic effect in guinea pigs. Lepp et al?"^"^ 

 reported that administration of ascorbic acid results in a small increase in 

 hemoglobin in chicks when used with a diet partially deficient in PGA. 

 Johnson and Dana"^ observed that supplying ascorbic acid to rats depleted 

 of PGA produced a gain in weight and a return of the white cell count to 

 normal and prevented further development of ''chromodacryorrhea" (achro- 

 iocythemia?). The hemoglobin continued to decrease, however, and there 

 was no reticulocyte response until after administration of PGA. Woodruff 

 and Darby-^^ also found a relation between ascorbic acid and PGA. The 

 administration of either PGA or ascorbic acid to guinea pigs on a scorbuti- 

 genic diet containing 5 % tyrosine caused a decreased excretion of tyrosyl 

 derivatives and keto acids. Dietrich et al.^'^^ observed that ascorbic acid 

 stimulates the synthesis of folic acid in the chick and considered the stimu- 

 latory action to be that of an oxidation-reduction mechanism rather than 

 one of a specific vitamin action. Recent investigations^^"' ^^^ have shown 

 that folic acid is present in natural materials in the form of folinic acid, 

 and it has l)een demonstrated that ascorl)ic acid enhances the conversion 

 of folic to folinic acid both in vivo^^- and in vitro. ^^^ The suggestion has been 

 advanced that the change from folic to folinic acid is associated with the 

 transfer of single carbon units. It has also been postulated that it is not 

 only the complete folinic acid molecule as such which has biological activ- 

 ity, but also tetrahydrofolic acid.^^^ The exact role of ascorbic acid in the 

 folic-folinic acid relation is not known, but it is possible that it has a stabil- 

 •zing effect on folinic acid, owing to its antioxidant action. The finding of 



"5 J. M. Hundley and R. B. Ing, Federation Proc. 12, 417 (1953). 



"« F. N. Silverman and B. Mackler, Proc. Soc. Exptl. Biol. Med. 76, 574 (1951). 



3" A. Lepp, P. R. Moore, C. A. Elvehjem, and E. B. Hart, Poultry Sci. 26, 594 (1947). 



"8 B. C. Johnson and A. S. Dana, Science 108, 210 (1948). 



"9 L. S. Dietrich, C. A. Nichol, W. J. Monson, and C. A. Elvehjem, J. Biol. Chem. 181, 



915 (1949). 

 38» J. A. Brockman, Jr., B. Roth, H. P. Broquist, M. E. Hultquist, J. M. Smith, 



M. J. Fahrenbach, D. B. Cosulich, R. P. Parker, E. L. R. Stokstad, and T. H. 



Jukes, J. Am. Chem. Soc. 72, 4325 (1950). 

 3" K. Schwarz, Federation Proc. 10, 394 (1951). 



382 C. A. Nichol and A. D. Welch, Proc. Soc. Exptl. Biol. Med. 74, 52 (1950). 

 '^^ W. Shive, T. J. Bardos, T. J. Bond, and L. L. Rogers, /. Am. Chem. Soc. 72, 2817 



(1950). 

 '84 H. P. Broquist, M. J. Fahrenbach, J. A. Brockman, Jr., E. L. R. Stokstad, and 



T. H. Jukes, /. A7n. Chem. Soc. 73, 3535 (1951). 



