42 P-AMINOBENZOIC ACID 



were killed with ether and the tumors were removed, freed from surround- 

 ing tissue, and weighed. The reversal of the tumor-inhibiting effect of 100 

 7 of inositol was found to be complete with 100 7 of injected PABA. Fifty 

 micrograms of PABA was described as reversing only partially the 100 7 

 of inositol. 0- and m-Aminobenzoic acids were described as much less effec- 

 tive antagonists of inositol than PABA. 



Although the tumor-inhibiting effect of inositol against mammary adeno- 

 carcinoma of mice has been confirmed by Hesselbach and Burk,^^* Harris 

 et al}'^^ found that neither inositol nor PABA has any effect on p-dimethyl- 

 aminoazobenzene carcinogenesis in rats. It may be pointed out that others 

 have reported that PABA has a retarding effect in chronic myelogenous 

 leukemia (see separate section) which is just the reverse of its reported 

 effect in antagonizing a tumor-inhibiting compound. 



3. Hamsters 



Cooperman et al}^^ reported that weanling hamsters fail to grow and die 

 when receiving purified diets containing the six B vitamins — thiamine, 

 riboflavin, calcium pantothenate, pyridoxine, nicotinic acid, and choline 

 plus biotin. When the diet is supplemented further with PABA and inositol, 

 there are fewer deaths. They conclude that PABA and/or inositol is re- 

 quired by the growing hamster. Here, again, PABA may be functioning as 

 a source stimulant for the synthesis of folic acid. 



4. Chicks 



Ansbacher^^ reported that chicks fed a ration consisting largely of wheat 

 middlings and yellow corn that had been heated at 110° for about one 

 week are stimulated in growth w^hen the diet is supplemented with 300 7 

 of PABA per gram of diet. Similarly Briggs et al}^ found that PABA at 

 levels of 5 to 15 mg. per 10 g. of diet produces growth responses in chicks 

 receiving purified diets low in folic acid but complete in all other respects. 



5. Swine 



Cunha et al}^'^ found that during a seven-week feeding experiment with 

 growing pigs no beneficial effect on external appearance, growth, or effici- 

 ency of feed utifization is obtained when either PABA or folic acid is added 

 alone or in combination with inositol and biotin to a purified basal ration 

 which contains the six B complex vitamins — thiamine, riboflavin, niacin, 



"4 M. L. Hesselbach and D. Burk, Record Chem. Prog. 5, 37 (19-14). 



'»5 P. N. Harris, M. E. Krahl, and G. H. A. Clowes, Cancer Research 7, 162 (1947). 



'""J. M. Cooperman, H. A. Waisman, and C. A. l]lvchjem, Proc. Soc. Exptl. Biol. 



Med. 52, 250 (1943). 

 "" T. J. Cunha, L. K. Jiustad, W. E. Ham, D. R. Cordy, E. C. McCulloch, I. F. 



Woods, G. H. Conner, and M. A. McGregor, /. Nutrition 34, 173 (1947). 



