THE FOLIC ACID COMPLEX 



In a patient with pernicious anaemia, receiving 0-85 mg. of syn- 

 thetic folic acid daily, approximately 15 % was excreted in the urine. 

 Following the intramuscular injection of 30 mg. of conjugate, no 

 increase occurred in the amount of folic acid excreted, but the injection 

 of a further 11 mg. resulted in the excretion of 4-1 mg. in the following 

 48 hours. 2 On the other hand, a normal individual, whose output of 

 folic acid was consistently 3 /xg. per day, excreted 10 to 22 % respec- 

 tively of a dose of 800 /xg. of synthetic folic acid given intramuscularly 

 on each of two successive days and 8-4 and 8-2 % respectively of an 

 equivalent dose (2800 /xg.) of the conjugate similarly injected. This 

 observation supports the theory that pernicious anaemia is character- 

 ised by inability to utilise folic acid conjugate (see page 500). 



The effect of pteroic acid on the urinary excretion of folic acid was 

 studied by Franklin et al.^ Following the oral administration of 2 to 

 10 mg., only a small amount of pteroic acid was excreted in the urine, 

 whereas after intravenous injection 15 to 46 % was recovered in the 

 urine. Only about i % was recovered in the form of pteroylglutamic 

 acid, h6wever, so that pteroic acid was poorly absorbed from the 

 gastro-intestinal tract and only a very small proportion of injected 

 material was converted into pteroylglutamic acid. 



Denko et al.^ observed that more folic acid was excreted in the 

 faeces than in the urine and that both together exceeded the dietary 

 intake, confirming that a synthesis of folic acid takes place to a con- 

 siderable extent in man, just as it does in animals. Other evidence 

 indicates that this synthesis is effected by the intestinal flora (see 



page 505). 



Humans excrete folic acid in the sweat, ^ and the amount may be 

 5- or 6-fold the amount eliminated per hour in the urine imder condi- 

 tions of profuse sweating. 



Following the intravenous injection of pteroylglutamic acid or 

 the triglutamate, an increase in the blood concentration took place 

 which reached a maximum two hours later. ^ When the triglutamate 

 was injected intramuscularly, two-thirds of the amount remaining in 

 the blood-stream two hours later was present in the form of the 

 monoglutamate."^ The blood of many animals, including man, 

 contains folic acid conjugase capable of releasing pteroylglutamic acid 

 from the heptaglutamate.^ 



References to Section 11 



I. R. Steinkamp, C. F. Shukers, J. R. Totter and P. L. Day. Proc. 



Soc. Exp. Biol. Med., 1946, 62, 556. 

 la. T. H. Jukes, A. L. Franklin, E. L. R. Stokstad and J. W. Boehne, 



/. Lab. Clin. Med., 1947, 32, 1350. 

 lb. P. L. Day and J. R. Totter, /. Nutrition, 1948, 36, 803. 



504 



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