ANEURINE (thiamine) 



i8. FUNCTION OF ANEURINE 

 Lactic Acid 



As long ago as 1914, C. Funk ^ suggested that vitamin B^ was 

 concerned with carbohydrate metabolism, and the first step towards 

 an imderstanding of its more precise function was taken in 1929 when 

 H. W. Kinnersley and R. A. Peters ^ showed that avitaminous pigeon 

 brain contained more lactic acid than did normal brain. T. W. 

 Birch and L. J. Harris ^ suggested that the bradycardia of vitamin 

 Bj-deiicient animals was correlated with the accumulation of lactic 

 acid in the organism, although they did not consider that the symptoms 

 were directly attributable to the presence of the acid, since brady- 

 cardia was not produced by injection of sodium lactate solution. 



H. G. K. Westenbrink,* however, claimed that either pyruvic acid 

 or lactic acid was the toxic metabolite responsible for some of the 

 symptoms of vitamin B^ deficiency, and in a more recent paper, it 

 has been claimed ^ that convulsions similar to those resulting from 

 vitamin B^ deficiency are produced in pigeons by injection of lactate 

 or pyruvate solution and that, provided not more than 0-15 ml. of a 

 2 % solution has been administered, the symptoms can be relieved by 

 the intravenous injection of 2000 to 5000 I.U. of vitamin B^. 



Whether the physiological effects observed in vitamin B^ de- 

 ficiency are due to an accumulation of lactic or pyruvic acid or of 

 some other substance, the fact that these substances do accumulate 

 both in the blood and the urine, instead of being further metabolised, 

 cannot now be questioned. 



Pyruvic Acid 



B. S. Piatt and G. D. Lu^ showed that the blood of beriberi patients 

 contained not only pyruvic acid, but other ketonic substances as well. 

 The amount of ketone bodies increased on exertion and the increase 

 was accompanied by clinical manifestations of fulminating beriberi 

 with cardiac symptoms. They did not believe that these cardiac 

 symptoms were directly attributable to the accumulation of pyruvic 

 acid, however. 



Bisulphite-binding Substances in Blood 



Attempts have been made to use the increase in ketonic substances 

 in the blood to assess the degree of vitamin B^ deficiency. Thus 

 Shils et alJ observed that in rats on a diet low in vitamin B^, the 

 increase in bisulphite-binding substances (B.B.S.) in the blood was 

 proportional to the extent of the deficiency. The increase was stated 

 to be due mainly to the accumulation of pyruvic acid. A. Goth ^ 



90 



