C H AFTER IV 



NICOTINIC ACID (NIACIN) 



I. INTRODUCTION 



The term " pellagra " was originally used rather loosely to describe 

 a condition characterised by a bilaterally symmetrical eruption. As 

 far back as 1918, J. Goldberger, G. A. Wheeler and V. P. Sydenstricker/ 

 claimed that pellagra, as thus defined, included at least two aetio- 

 logically distinct syndromes, and suggested that two dietary factors 

 might be involved. Seven years later, J. Goldberger and W. F. 

 Tanner ^ announced that pellagra could be cured by yeast and called 

 the responsible factor the PP (pellagra preventative) factor. 



Pellagra is largely a disease of warm climates, and has always 

 been associated with the use of maize as the staple cereal, though oats 

 and rye may also produce pellagra if used as the sole cereal. Pellagra 

 assumes a variety of forms, mainly because other members of the 

 vitamin B complex besides the pellagra preventative factor are in- 

 variably deficient in or missing from the pellagra-producing diet. 



The use of experimental animals in the investigation of pellagra 

 did not meet with immediate success ; indeed, the use of the three 

 species, rats, chicks and dogs, only led to bewildering and often con- 

 tradictory results, which at the time were extremely difficult to inter- 

 pret. Thus a dermatitis similar to pellagra was produced artificially 

 in rats by J. Goldberger and R. D. Lillie,^ using a ration to which 

 adequate amounts of an antineuritic concentrate had been added ; 

 the rats were cured by administration of autoclaved yeast, and it was 

 hoped that a satisfactory animal test for the new factor had been 

 discovered, thus facilitating research on its isolation and identification. 

 These hopes were not realised, however, for it was found difficult to 

 use the onset of dermatitis as the basis of a quantitative method of 

 assaying the PP-f actor content of foodstuffs. It therefore became 

 customary to assay these by the growth produced in rats. W. R. 

 Ackroyd, however, found that maize, the pellagra-producing cereal 

 par excellence (see page 240), produced good growth in rats, and it 

 became evident that the rat-growth method was not assaying the 

 PP-f actor at all, but another factor, later shown to be riboflavine. 

 Much of the old literature in which this method is used is, therefore, 



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