ANEURINE (thiamine) 



page 28), is used for the biological assay of vitamin B^ preparations. 

 Rats also develop convulsions and slowing of the heart -beat (brady- 

 cardia) on diets low in aneurine ; these symptoms have also been 

 proposed as the basis of bio-assay methods (see page 30). The 

 electrocardiogram shows a good response to aneurine treatment 

 within twenty-four to seventy- two hours. Changes in the electro- 

 cardiogram can be observed about a week before other signs become 

 evident. ^3 In addition, a condition of anoestrus is produced and can 

 be cured by administration of aneurine ; ^* the accompanying dis- 

 turbances of reproduction and lactation, however, are not cured until 

 the stock diet is given. Riboflavine deficiency also causes anoestrus, 

 and administration of riboflavine restores both the normal cycle and 

 normal reproduction and lactation. Attempts to use this condition 

 as the basis of a method of assaying aneurine were not very success- 

 ful ; ^^ it is not considered specific for aneurine. 



Other symptoms of vitamin B^ deficiency observed in rats are : ^^ 

 loss of appetite, without affecting the gain in weight per unit of food, 

 a decrease in the fat and energy output, a lower body temperature, 

 decreased efficiency in the utilisation of metabolisable energy, an 

 increased loss of energy as heat and by excretion in the urine, an 

 increased C : N ratio in the urine and an apparent depression of the 

 oxidative processes of the body. In addition achlorhydria, loss of 

 muscular tone and lesions of the nervous system may develop. ^^ 



Vitamin B^ deficiency resulted in a rapid and marked deterioration 

 of the work performance of swimming rats, and this was promptly 

 restored by the administration of aneurine ; ^^ reduction of the food 

 intake without rendering the diet deficient in aneurine did not decrease 

 the work performance. 



When yoimg rats were allowed to develop acute deficiency 

 symptoms, which were then cured by a small amoimt of aneurine and 

 the process repeated several times, most of the animals at autopsy 

 showed enlarged hearts due to dilatation of the right auricle ; a few 

 rats showed pleural effusions and ascites. ^^ The auricles generally 

 showed necrosis of the muscle fibres, cellular infiltration and prolifera- 

 tion or a decreased number of muscle fibres and fibrosis. Changes 

 in the ventricle were uncommon or slight. Half the rats showed 

 pathological changes in the pulmonary veins. 



Different strains of rats may behave differently towards aneurine, 

 a point to be carefully considered in bio-assay work. For example, 

 one highly inbred strain was observed ^^ to develop polyneuritis in 

 fifty-eight days, whilst another strain showed only mild deficiency 

 after ninety days. One result of vitamin B^ deficiency in rats is 

 marked creatinuria,^^ a correlation being observed between the ex- 

 cretion of creatinine and the bodyweight. Even in mild chronic 



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