772 XII. VITAMINS K 



Vitamin K is also able to counteract the action of a-tocopheiyl-qiiinone 

 in producing hemorrhagica symptoms in the reproductive system and the 

 resultant resorption in pregnant mice.^^^ Large doses of vitamin E were 

 found to be ineffective in reversing thise ffect. Woolley'^'^ suggests that 

 the similarity in structure of a-tocopheryl-quinone and vitamin K may 

 account for the effectiveness of the latter. 



7. Vitamin K Hypovitaminosis 



{1 ) Methods of Producing Deficiency 



a. Dietary Lack of Vitamin K. Although the classical method for pro- 

 ducing vitamin deficiencies by feeding the animal on a vitamin-deficient diet 

 is quite effective in the case of the chick, for vitamin K/^'* and in ducklings 

 and young geese/^^ it is difficult to produce the deficiency in other animals 

 solely by dietary means. This is due to the fact that, in the chick, although 

 vitamin K is produced in the lower intestinal tract, it cannot be absorbed 

 from this portion of the intestine.** Almquist and Stokstad** reported 

 the presence of vitamin K in the droppings of vitamin K-deficient chicks. 

 On the other hand, sufficient vitamin K is normally synthesized in some 

 areas of the intestinal tract of other species as to allow the absorption of 

 enough of the vitamin to prevent severe vitamin K-avitaminosis. One 

 exception to the above is the development of vitamin K deficiency symp- 

 toms in the newborn. Thus, the newborn of man,*"-^^^ as well as of sheep 

 and goats, ^^^ and of the guinea pig,^^^ are lacking in vitamin K at birth. 

 Since the gastrointestinal tract is sterile at birth, no vitamin K is available 

 from this source. Under such conditions, the prothrombin is reduced to 

 dangerously low levels if vitamin K is not given by mouth or administered 

 parenterally. There is even the possibility that death may result. As 

 soon as food is taken and the hitestinal flora are established, the synthesis 

 of vitamin K begins, and prothrombin formation follows the absorption of 

 the vitamin. 



However, Dam and Glavind^* demonstrated that it was possible to 

 produce a low grade avitaminosis K by feeding animals a diet low in vita- 

 min K over a prolonged period. Murphy'^* confirmed these findings in 



193 D. W. Woolley, J. Biol. Chem., 159, 59-66 (1945). 

 18^ H. Dam, F. Sch0nheyder, and L. Lewis, Biochem. J., 31, 22-27 (1937). 

 195 w. W. Waddell, Jr., D. Guerry, III, W. E. Bray, and O. R. Kelley, Proc. Soc. Exptl. 

 Biol. Med., 40, 432-434 (1939). 



19^ A. van Vyve, Acta Brevia Need. Physiol. Pharmacol. Microbiol, 11, 101-104 (1941 ). 

 1" F. Widenbauer and U. Krebs, Monatsschr. Kinderheilk., 91, 223-225 (1942). 

 "8 R. Murphy, Science, 89, 203-204 (1939). 



