IX. EFFECTS OF DEFICIENCY 17 1 



and Home Economics and the Texas Agricultural Experiment Station. ^ 

 In addition to values for total PGA content measured by the L. casei 

 assays, as listed in the table, assays were also made with S. faecalis for 

 both free and conjugated forms. Bound PGA was measured after digestion 

 with chicken pancreas enzyme. 



IX. Effects of Deficiency 



A. IX AXLMALS 



E. L. R. STOKSTAD 



X'arious animal species differ markedly in their requirement for PGA. This 

 reflects in part their ability to utilize bacterial intestinal synthesis as a 

 source of the vitamin. The chick, the monkey, and the guinea pig develop 

 deficiencies on a purified diet low in the vitamin. The rat, on the other hand, 

 constitutes an excellent example of an animal that is capable of meeting 

 its dietary requirements for PGA by intestinal synthesis; consequently, 

 deficiencies of this vitamin were not recognized in the rat until intestinal 

 antiseptics such as sulfonamides were employed. Other species, such as the 

 dog, do not develop deficiencies on a purified diet even with the use of in- 

 testinal antiseptics, and PGA antagonists are necessary to produce a de- 

 ficiency syndrome. 



1. Rats 



a. Production of PGA Deficiency by Sulfonamide Feeding 



Rats can be grown on a diet free of PGA without development of any 

 deficiency symptoms unless an intestinal antiseptic is added or a stress is 

 imposed which increases the requirement of the vitamin. Black et al} 

 showed that addition of a sulfonamide depressed the growth rate which 

 could then be restored in the presence of the sulfonamide by the feeding of 

 liver extracts. Shortly after this, Spicer and coworkers- at the National 

 Institutes of Health observed hematological changes including leucopenia, 

 agranulocytosis, hypocellularity of the bone marrow, and less frequently 

 anemia, on diets containing sulfaguanidine or sulfasuxidine (succinylsul- 

 fathiazole). These symptoms could be prevented or cured by the feeding of 



' E. W. Toepfer, E. G. Zook, M. L. Orr, and L. R. Richardson, U. S. Dept. Agr., 



Agr. Handbook 2^ (1951). 

 ' S. Black, J. M. M(Kil)l)in, and C. A. Elvolijem, Proc. Soc. Exptl. Biol. Med. 47, 



308 (1941). 



= S. S. Spicer, F. S. Daft, W. H. Sebrell, and L. L. Ashbum, Public Health Kepis. 



(U. S.) 57, 1559 (1942). 



