HUMAN AND ANIMAL REQUIREMENTS 



increasing the daily intake of the vitamins, but yielded to treatment 

 with biotin and a folic acid concentrate, illustrating the close associa- 

 tion between different members of the vitamin B complex. The 

 authors concluded that the utilisation of pantothenic acid depended 

 on the availability of biotin and folic acid. 



Pantothenic acid deficiency in the rat was accentuated by feeding 

 purified beef blood fibrin in place of casein,* possibly because this 

 source of protein was less favourable than casein for the growth of the 

 intestinal flora. 



Direct evidence that pantothenic acid is synthesised by the intes- 

 tinal flora in man was obtained by Denko et al.,^ who found that both 

 on a normal and on a restricted diet the combined faecal and urinary 

 excretion exceeded the dietary intake, although not to the same 

 extent as with ^-aminobenzoic acid, folic acid and biotin (see page 

 435). Moreover, although on the restricted diet the urinary excretion 

 was increased by administration of pantothenic acid, the faecal ex- 

 cretion was virtually independent of the dietary intake. It is not 

 certain whether or not the pantothenic acid formed by the intestinal 

 bacteria can be utilised in man. 



References to Section 11 



1. L. W. McElroy and H. Goss, /. Nutrition, 1941, 21, 405. 



2. H. D. West, N. C. Jefferson and R. E. Rivera, ihid., 1943, 25, 



471. 



3. L. D. Wright and A. D. Welch, Science, 1943, 97, 426 ; /. Nutrition, 



1944, 27, 55- 



4. M. M. Nelson and H. M. Evans, Proc. Soc. Exp. Biol. Med., 1947, 



66, 299. 



5. C. W. Denko, W. A. Grundy, J. W. Porter, G. H. Berryman, T. E. 



Friedemann and J. B. Youmans, Arch. Biochem., 1946, 10, 33 ; 

 C. W. Denko, W. E. Grundy, N. C. Wheeler, C. R. Henderson, 

 C. H. Berryman, T. E. Friedemann and J. B. Youmans, ibid., 

 1946, 11, 109. 



12. HUMAN AND ANI2V1AL REQUIREMENTS 

 OF PANTOTHENIC ACID 



There is surprising unanimity in the figures quoted by different 

 authors for the pantothenic acid requirement of the rat, most workers 

 agreeing that the minimal dose necessary to prevent achromotrichia 

 and produce adequate growth lies between 50 and 100 fig. per day.^"^ 

 Estimates of the dose required to cure achromotrichia range from 20 

 to 40,^ 50 ^ and 100 fig. per day,^ whilst the following amounts have 

 been suggested as being necessary to promote growth : 40,^ 50, ^'"^ 



377 



