EFFECT OF DEFICIENCY IN ANIMALS 



Riboflavine and Cancer 



Cancer tissue contained amounts of riboflavine similar to those 

 present in brain, lung, spleen and muscle. 2* The absence of ribo- 

 flavine from the diet of C3H mice reduced the growth rate of spon- 

 taneous mammary tumours as well as the growth rate of the animal 

 whilst the addition of riboflavine to the diet increased the average 

 number of tumours per mouse. ^^ Complete regression of lympho- 

 sarcoma implants followed the temporary induction of riboflavine 

 deficiency in mice.-^" 



When certain carcinogenic dyes w^ere added to the diet of rats, 

 the riboflavine content of the liver decreased, the decrease being 

 approximately proportional to the carcinogenicity.^^ w'-Methyl-^- 

 dimethylaminoazobenzene was the most effective of the compounds 

 tested. More riboflavine w^as stored in the liver when the basal diet 

 contained 24 % of casein than with 12 %, but the relative effects of 

 the carcinogens was the same on either diet. Although the food 

 intake was reduced when the azo dyes were fed, this was not responsible 

 for the change in vitamin storage. Limitation of the riboflavine 

 intake reduced the ability of rat liver slices to destroy NN-dimethyl- 

 _/)-aminoazobenzene . ^ ^" 



Effect on Infected Animals 



The effect of riboflavine deficiency on the resistance of experi- 

 mental animals to infection varied according to the nature of the 

 invading organisms. For example, mice fed a diet deficient in ribo- 

 flavine w^ere said to be more susceptible then normal mice to Pneumo- 

 cocciis Type I.^'' A similar result was obtained with aneurine-deficient 

 animals, and the effect was show^n not to be due to the restricted food- 

 intake. On the other hand, treatment with riboflavine or aneurine 

 at the time of infection did not appear to affect the mortality rate. 



Ribofiavine-deficient mice were also said to be more susceptible 

 than normal mice to a spontaneous Salmonella infection, ^^ whereas 

 they were apparently less susceptible than normal mice to the Lansing 

 strain of the influenza virus. ^^ Similarly, ribofiavine-deficient chicks 

 exhibited less severe symptoms when infected with Plasmodium 

 lophurae than did nonnal chicks, and the severity of the disease 

 appeared to increase on administration of riboflavine.^^ Finally a 

 deficiency of riboflavine (or aneurine) reduced the resistance of rats 

 to infection by the worm, Nippostrongylus muris, and plasma from 

 riboflavine- (or aneurine-) deficient animals was less effective than 

 immune sera from normal animals in combating the infect ion. ^^ 



The absence of any clear-cut connection between the susceptibility 



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