NICOTINIC ACID (NIACIN) 



the treatment of what may be termed " classical " pellagra ; 50 to 

 500 mg. of nicotinic acid a day cured the dermatitis in the acute form 

 of the disease and 150 to 500 mg. a day in the chronic form. Doses 

 up to 500 mg. controlled the diarrhoea, but not the neuritis or mental 

 symptoms. 2* Nicotinamide in 50-mg. doses effected prompt improve- 

 ment in patients with atrophy of the tongue, fissures of the tongue or 

 atrophy of the papillae. ^^ 



Excretion of Pigment 



Pellagrins excrete a red pigment in the urine. According to C. J. 

 Watson,26 this was not porphyrin, but urorosein,^' derived from its 

 chromogen, indolylacetic acid,^^ by the action of other substances, 

 e.g. nitrites, present in the urine of pellagrins ; ^9 indirubin or a closely 

 related substance was also present. ^^ These pigments were not 

 observed in normal urine, although indolylacetic acid is ordinarily 

 present, being excreted by subjects who exhibit no clinical symptoms 

 of nicotinic acid deficiency.^^ There appears to be no correlation 

 between the presence of the chromogen and nicotinic acid deficiency 

 or its disappearance on administration of nicotinic acid, but the con- 

 version to urorosein appears to take place spontaneously only in 

 association with the disease. Urorosein was not present in urine from 

 dogs with blacktongue, nor was there any increase in the copropor- 

 ph5n:in excretion in canine blacktongue.^^ 



The excessive coproporphyrinuria, frequently reported in alco- 

 holic pellagrins (see page 245), is believed by C. Rimington and Z. A. 

 Leitner ^^ to be due to liver damage by the alcohol or by the dietary 

 deficiency. Out of fifteen proved cases of pellagra, only two showed 

 excessive porphyrinuria, and these were explicable on other grounds. 

 It was concluded that porphyrinuria is not an essential feature of 

 pellagra. 



" Pseudo-pellagrous Conditions '* 



Although " classical " pellagra is due to a deficiency of nicotinic 

 acid, related conditions are known in which a deficiency of other 

 members of the vitamin B complex co-exists with a nicotinic acid 

 deficiency and, in this event, the clinical picture is atypical. Again, 

 other examples of nicotinic acid deficiency occur, in which the causes 

 are different from those leading to true pellagra. For convenience, 

 these various forms of nicotinic acid deficiency have been referred to 

 as " pseudo-pell agrous conditions ". 



All such cases are benefited by nicotinic acid or nicotinamide, and 

 in some a complete cure may result. In others, however, additional 

 members of the vitamin B complex have to be given, together with 



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