METABOLISM 



in the coenzyme I content of the liver and muscle of nicotinic acid- 

 deficient dogs and pigs. H. I. Kohn ^^ and Vilter et al.^^ observed 

 that the factor V content of the blood of pellagrins increased after ad- 

 ministration of nicotinic acid, whilst H. I. Kohn and J. R. Klein ^° 

 and Vilter et al.^^ showed that incubation of defibrinated blood with 

 nicotinic acid increased its factor V content. Ingestion of large 

 amounts of nicotinic acid increased the coenzyme I content of the 

 erythrocytes.®^ 



Using Bacillus influenzae, Vilter et al.^^* ^^ found that the factor V 

 content of the blood decreased in pellagra, but H. I. Kohn and F. 

 Bernheim,®* using H. parainfluenzae, failed to imd any significant 

 difference in the amount of factor V present in erythrocytes from 

 pellagrins, compared with controls. This was confirmed by Axelrod 

 et al.,^^ using the yeast fermentation method ; ®® they found that the 

 coenzyme I content of erythrocytes averaged 85 ixg. per ml. in controls, 

 77 and 69 /Ltg. per ml. in sub-clinical and mild pellagra respectively and 

 from 70 to 90 /Ag. per ml. in severe cases. The amount in muscle, on 

 the other hand, decreased from 382 in controls to 317, 258 and 214 

 ftg. per g. in sub-clinical, mild and severe pellagra respectively. 



Nicotinic Acid in Blood 



B. D. Kochhar,®' using acid hydrolysis followed by colour develop- 

 ment as in Swaminathan's method, found that the nicotinic acid 

 content of blood varied from 230 to 650 /ug. per 100 ml. with an 

 average value of 367 /xg. per 100 ml. These values presumably in- 

 cluded the free nicotinic acid, nicotinamide, nicotinuric acid and 

 coenzymes I and II, but not trigonelline or N^-methylnicotinamide. 

 Most of the nicotinic acid was present in the corpuscles, the value for 

 serum being 62 to 170, with an average of 92 /xg. per 100 ml. Cerebro- 

 spinal fluid was found to contain 56 to 120 with an average of 92 /u.g. 

 per 100 ml. of acid-hydrolysable nicotinic acid derivatives. 



Most of the nicotinic acid in dogs' blood was present in the red 

 cells, ®^ the actual values found being jy % in the erythrocytes, 12 % 

 in the leucocytes and 11 % in the plasma. Oral administration of 

 nicotinic acid increased the plasma nicotinic acid to a greater extent 

 than the erythrocyte nicotinic acid. Oral administration of 200-mg. 

 doses of nicotinic acid daily to humans slightly increased the blood 

 level up to a maximum value which was maintained as long as the 

 additional nicotinic acid was given. ®^ Oral administration of a single 

 dose temporarily increased the blood level, a peak being reached 

 after thirty minutes. 



Nicotinic acid was taken up quantitatively by red blood cells in 

 vitro and fixed in the cells in a non-diffusible form, presumably as 



263 



