FURTHER METABOLISM IX THE TISSUES 655 



was present in the corpuscles. -'^^ Warkany--^ gives figures for vitamin D 

 in whole blood varying between 40 and 67 I.U./IOO ml., depending upon 

 the quantity of the vitamin D administered. In the case of cattle, pigs, a 

 dog and a rabbit, Warkany--^ recorded figures for vitamin D in the blood 

 ranging from 50 to 100 I.U. ^100 ml. In the case of children and adults, 

 Warkany and ]\Iabon--^'- found the a\'erage for serum vitamin D to be 110 

 I.U. '100 ml. Warkany and collaborators-^^ observed that, when patients 

 were treated A\ith high doses of ^dtamin D, the serum ^■itamin D rose 

 steadily until values of 9,000 to 13,000 I.U. 100 ml. were obtained when 

 doses of 400,000 to 500,000 I.U. of \-itamin D were gi\'en daily, .\fter the 

 termination of the vitamin D dosing, the levels of vitamin D in the blood 

 returned to normal in the course of three to six months. On the other 

 hand, when Cruickshank and Kodicek-" fed 40,000 I.U. of xatamin D to 

 rats in a single dose, inconsequential amounts of the vitamin were re- 

 covered from the blood. 



3. The Further Metabolism of the Vitamins D in the Tissues 



Little information is a^'ailable as to the fate of the ^-itamins D after they 

 lesive the blood. In studies on dogs IMorgan and Shimotori-"^ recorded 

 the following values for vitamin D (expressed in I.U./g. tissue) : kidneys, 

 3 to 8; heart, ca. 5; wall of large intestine, ca. 5; and brain, lung, spleen, 

 muscle, stomach, abdominal fat, skin and hair, 0.3 to 1.0. 



Figures are also available for the \dtamin D concentration in human 

 tissues, usually after large (and unphysiologic) dosages. Thus, in the case 

 of an infant who died of pneumonia four days after the intramuscular 

 injection of 15 mg. of calciferol (^^tamin D), Houet^^^ observed the follow- 

 ing values (expressed in mg. per total tissue): brain, 1.6; kidneys, 0.64; 

 li\'er, 0.04; and muscle, 3.8 mg. 



It is impossible to arrive at an^'thing in the nature of a quantitative re- 

 co^'ery of unchanged \'itamin D when large doses are gi\-en to animals. 

 Although McChesney and Giacomino--^" accounted for 1000 I.U. in the 

 carcasses of chicks fed 2400 I.U. of ^dtamin D2 (about 40%), Morgan and 

 Shimotori-"^ were never able to recover more than 10% of the quantity 

 ingested in the case of dogs. Moreover, Kodicek-°^ demonstrated onlj^ 6% 

 of the ingested \dtamin D in the carcasses of weanhng rats fed 40,000 I.U. 



2" A. F. Hess, R. F. Light, C. N. Frev, and J. Gross, /. Biol. Chem., 97, 369-377 

 (i;)32). 



"2 J. Warkany and H. E. Mabon, A771. J. Diseases Children, 60, 60G-614 (1940). 



"3 J. Warkanv, G. M. Guest, and F. J. Grabill, J. Lab. Clin. Med., 27, 557-565 (1942). 



"* R. Houet, Ann. Paediat., 166, 169-176 (1946). 



235 E. W. McChesney and N. J. Giacomino, J. Nutrition, 29, 229-235 (1945). 



