XI. REQUIREMENTS AND FACTORS INFLUENCING THEM G93 



of calcium pantothenate daily to human subjects — these are, of course, 

 excessively large doses. The evidences of toxicity were an occasional diar- 

 rhea and, in three subjects with rheumatoid arthritis, retention of water 

 with edema of the face, the feet, and the lower parts of the leg occurred, 

 but it disappeared when calcium pantothenate was discontinued. This 

 latter observation is interesting because of the report by Gaunt et alP 

 concerning the disturbance in water tolerance tests in rats on diets deficient 

 in pantothenic acid, and also because of the effects of large doses of calcium 

 pantothenate on the survival of the completely adrenalectomized rat.^^' ^^ 

 In our own experiments on intact rats on high pantothenate intakes^^ we 

 observed a decrease in the water tolerance test. One would judge that cal- 

 cium pantothenate under certain circumstances was associated with the 

 retention of water. 



5. Summary 



On the basis of the data reported, it would appear that the approximate 

 daily intake of pantothenic acid in human subjects on a diet in the United 

 States varies from 3 to 12 mg. Judging from this and from the amounts 

 excreted daily, the amount of pantothenic acid in the diet is more than 

 adequate and protects against a deficiency of this vitamin. Combined with 

 the data in Fig. 11, it would appear that the daily requirement of panto- 

 thenic acid for adults is approximately 3 to 5 mg. The intake of pantothenic 

 acid is reflected in the urinary excretion, and when the diet is excessively 

 high the excretion will increase. The highest excretion reported on normal 

 diets was 5.3 mg. per 24 hours. The constancy of the fecal excretion indi- 

 cates good absorption of the vitamin. Probably the infant and growing 

 child would need relatively more pantothenic acid than the adult, approxi- 

 mately 5 mg. daily. On the basis of data previously mentioned on the effects 

 of the administration of very large doses of pantothenic acid to individuals 

 with a variety of metabolic disturbances, there seems to be no indication 

 that the requirement is significantly altered in these diseases. The proof 

 that the average human, at least in this country, has an adequate supply 

 of pantothenic acid is provided by the acetylation studies done in patients 

 with such severe diseases as cirrhosis of the liver, Addison's disease, and 

 diabetes mellitus. It is significant in this respect that patients with hyper- 

 thyroidism^i did not acetylate PABA as well as did normal subjects, and 

 probably in conditions of stress in humans and in situations where the 

 metabolic rate is significantly increased the pantothenic acid requirement 

 would be increased. 



82 R. Gaunt, M. Liling, and C. W. Mushett, Endocrinology 38, 127 (1946). 



83 E. P. Ralli, Endocrinologi/ 39, 225 (1946). 



84 M. E. Dumm and E. P. Ralli, Endocrinology 43, 283 (1948). 



85 M. E. Dumm and E. P. Ralli, unpublished data. 



