ANEURINE (thiamine) 



varied enormously — from 1:9 to 9:1. Administration of aneurine 

 increased the excretion of both forms and generally left the ratio 

 substantially unaffected. 



The presence in urine of a pyrimidine compound capable of stimu- 

 lating the growth of yeast in a manner similar to anemine was reported 

 by Pollack et al.^^ They found that on depriving a subject of aneurine 

 for ten days the ratio of aneurine to pyrimidine changed from 9 : i to 

 1:9, the absolute amount of the pyrimidine excreted remaining sub- 

 stantially constant. The intravenous injection of 100 mg. of aneurine 

 was followed by an enormous increase in the excretion of urinary 

 pyrimidine. 



A novel method of studying the metabolism of aneurine was 

 introduced by Borsook et al.^^ They injected aneurine containing 

 radioactive sulphur, S^^, intramuscularly into a man who had been 

 deprived of aneurine for thirty-six days, and found that there was a 

 rapid increase in the excretion of S^^ in the urine, indicating that signifi- 

 cant amounts of aneurine remained in the tissues after prolonged 

 ingestion of a vitamin Bj-free diet. The results also showed that in- 

 jected aneurine interacted very quickly with pre-existing aneurine in 

 the blood and tissues, and that metabolism was very rapid, yielding 

 neutral sulphur compounds and inorganic sulphate in the urine. 



The efficiency with which different amounts of aneurine are 

 utilised in the rat varies, but doses of 5 to 50 /xg. per day were the 

 levels most effectively utilised. 20 The efficiencies for doses of 50, 100 

 and 1000 /xg. per day were 92, 83, and 52 % respectively. The results 

 indicate that appreciable destruction of aneurine occurs in the body. 

 Such destruction was shown to take place when anemine was incu- 

 bated with liver, lung, heart, stomach and intestinal tissue. Com- 

 parable figiures are not available for humans, but it has been shown 21 

 that in normal subjects the urinary excretion is directly related to the 

 dose given and, with intakes of 50 mg., approximates to 100 %. On 

 a synthetic diet yielding i mg. of aneurine per day and on a natural 

 diet containing 0-84 mg., the daily urinary outputs were 113 to 147 

 and 90 to 112 /xg. respectively. 22 



Doubt was thrown on the validity of the excretion test method of 

 assessing aneurine status by E. C. Allbone and E. Finch,^^ who found 

 that children on an ordinary diet excreted in the urine 10 to 14 % of 

 their intake of aneurine and that after giving 0-5 to i-o mg. by mouth, 

 the output in different individuals varied considerably — from o to 

 41 % — but the average was still only 14 %. Many recently ill children 

 excreted amounts of aneurine considerably less than the accepted 

 levels without showing signs of beriberi. 



Somewhat disturbing results were also obtained by H. H. Gifft 

 and H. M. Hauck,^^ who compared four different methods of assessing 



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