X. EFFECTS OF DEFICIENCY 



287 



evrii in t'uUy dc^Nclopcd \it;iMiiii H,-, (l(>lici(Micy, may stay witliiii noiniul 

 limits.'"' ""* (iivcnlu'ij; and co-woikcrs'-'^ studied the same pliciiomciioii in 

 three human subjects on a vitamin Be-dehcient diet for 1 to 3 weeks (chielly 

 casein-sucrose-oil and vitamins), followed by an additional week durinj;; 

 which they received d-iily supplements of pyridoxine (10 or 15 mj^.)- A'he 

 results summarized in the followinj^ t ible indicat.' that human subjects 

 may develop early on a vitamin Bc-deficient diet a derangement of trypto- 



TABLE V 

 Xanthurenic Acid Excretion'** 



Subject 



Dietary status 



Pyridoxine supplement 



Excretion, mg./24 hr. 



Before After 



tryptophan tryptophan 



D. B. Synthetic diet for 21 days 

 Sj'iithetic diet for 28 days 



Natural diet (control 



period) 

 Synthetic diet for 7 da3'S 

 Synthetic diet for 14 days 



H. M. Synthetic diet for 21 days 

 Synthetic diet for 28 days 



Natural diet for 38 daj-s 



N. K. Natural diet (control 

 period) 

 Synthetic diet for 6 days 



phan metabolism, manifested by the excretion of xanthurenic acid after an 

 extra load of tryptophan (Table V) . 



The xanthurenic acid index may be used as a biochemical sign of a latent 

 vitamin Be deficiency or at least of an increased requirement for vitamin Be . 

 The xanthurenic acid index is expressed as the percentage of the dose of 

 tryptophan, the latter given in an amount of 0.1 g. per kilogram of body 

 weight. '^^ In five non-pregnant women Vandelli found ''■''■' that the index 

 ranged from 0.25 to 1.50. In six pregnant women it ranged from 2.13 to 

 12.4, the higher values tending to occur later in pregnancy. In three preg- 



1" L. D. Greenberg, D. F. Bohr, H. McCrath, and .1. F. Hincliart, Arch. Biochnn. 21, 



237 (1949). 

 '«* F. M. Chiancone, Acta Vitaminol. 4, 193 (1950). 

 '99 I. Vandelli, Acta Vitaminol. 5, 55 (1951). 



