498 



V. BLOOD LIPIDS 



ministered daily. This is the smallest dose which results in any detectable 

 deposition of vitamin A in the liver. However, the apparently normal 

 vitamin A level in the plasma is evidently not reached until 30 fig. has 

 been given, it remains constant when ten times the dose is administered. 

 The retina has an almost constant vitamin A content throughout, while the 

 liver vitamin A increases progressively after the dosage is high enough to 

 permit storage in that organ. When a massive dose of vitamin A was given 

 (30,000 ng. daily), the rats suffered from hypervitaminosis A, and 30% 

 died. However, the serum, liver, and retina all contained the highest 

 vitamin A levels recorded in any of the tests. 



a'. Vitamin A Tolerance Curves: A number of workers have assessed 

 the vitamin A status of man by the effect of fixed doses of vitamin A on the 

 blood picture. When this procedure was employed by Krause and Pierce 862 

 in the case of school children who received either 7500 or 15,000 fig. (25,000 

 or 50,000 LIT.) of vitamin A in a single dose, the data recorded in Table 20 

 were obtained. No differences are evident, for the children with and 

 without folliculosis, respectively, in the fasting levels of vitamin A in the 

 plasma or in those resulting after the administration of fixed doses of 

 this vitamin. 



Table 20 



Vitamin A Content in Sera of School Children with and without Folliculosis, 



Following the Ingestion of Single Doses of Vitamin A° 



Group I Group II 



Category Control Folliculosis Control Folliculosis 



Number of children 5 7 12 12 



Vitamin A administered, 



Mg 7500 7500 15000 15000 



Plasma vitamin A, ng.% h 



hours (basal) 26 ± 7.6 24 ± 5.4 27.6 ± 5.4 28.0 ± 6.9 



4 hours after 68 ± 26.2 41 ± 24.0 67.2 ±31.2 50.8 ± 10.9 



5 " " 68 ± 23.4 68 ± 20.8 123.8 ± 49.0 123.9 ± 20.8 



6 " " 68 ± 27.8 65 ± 39.2 87.0 ± 26.9 95.5 ± 13.1 



8 - " 45 ± 17.9 38 ± 9.8 52.9 ± 26.9 67.3 ± 6.7 



24 " " 48 ± 7.0 25 ± 5.8 35.5 ± 6.9 40.6 ± 4.4 



« Adapted from R. F. Krause and H. B. Pierce, J. Nutrition, S3, 633-640 (1947). 

 b Including Standard Deviation of the Mean. 



Although no appreciable differences were observed in the curves for 

 serum vitamin A between the "normal" children and those having follicu- 

 losis, the maximum levels obtained on the two dosages are quite different. 

 Thus, after 15,000 jug. of vitamin A had been given, the maximum blood 



