REQUIREMENTS FOR VITAMIN K 779 



In a comparison of the rate of action of several vitamin K-active com- 

 pounds, Dam and S0ndergaard-^^ reported that vitamin Ki, menadione, 

 and Sy7ikavit (the tetrasodium or tetracalcium salt of 2-methyl-l,4- 

 naphthoquinone diphosphate) had approximately equal biologic activities, 

 on a molar basis, against vitamin K deficiency when tested by the usual 

 assay method with chicks over a period of twenty hours. However, after 

 the intravenous injection of vitamin Ki the effect on prothrombin forma- 

 tion began sooner with vitamin Ki than with the other related products. 



In the case of the newborn, Dyggve, Dam, and S0ndergaard-'*^ found 

 that vitamin Ki and Synkavit gave approximately the same response when 

 administered either intravenously or orally. On the other hand, when an 

 aqueous colloidal solution of vitamin Ki {Konakion) was given at dosages 

 of 20 or 40 mg. one hour before delivery, 2^" it was as effective as Synkavit, 

 as determined by the influence upon the prothrombin time of the newborn 

 during the first six days after birth. At low'er dosages, Synkavit was 

 definitely superior. Mtamin Ki dissolved in peanut oil was found to be 

 much less effective than when given in an aqueous colloidal solution. ^s" 

 Dam and Glavind-^'* reported that vitamin K was equally active in raising 

 the prothrombin content of the blood in chickens with avitaminosis K, 

 whether the condition was produced by dietary restriction or was induced 

 by ligature of the bile duct. 



10. The Requirements for Vitamin K 



{!) Requirement for the Chick 



More data are available on the rec|uirement of vitamin K for the chick 

 than for other animals. The blood-clotting time, which is an index of the 

 state of vitamin K reserves, depends upon the vitamin K intake of the 

 parent hen. Almquist et al.-^^ reported that a diet containing 2.5% of 

 alfalfa meal provided protection for the chick. Cravens and co-workers-^^ 

 found that the blood-clotting time and prothrombin levels of day-old 

 chicks were a reflection of the vitamin K content of the diet of the parent 

 hen. One or two per cent of dried alfalfa or grass w^ere found to be suffi- 

 cient to provide the necessary protection for the newly-hatched chick, 



248 H. Dam and E. S0ndergaard, Acta pharmacol. et toxicol., 9, 131-136 (1953). 



^^^ H. V. Dyggve, H. Dam, and E. S0ndergaard, Acta Paediatrica, 43, 27-31 (1954). 



2M H. V. Dvggve, H. Dam, and E. S0ndergaard, Acta Obst. Gyn. Scandinav., 33, 283- 

 288(1954). 



-" H. J. Almquist, E. Mecchi, and A. A. Klose, Biochem. J., 32, 1897-1903 (1938). 



262 W. W. Cravens, S. B. Randle, C. A. Elvehjem, and J. G. Halpin, Poultry Sci., 20, 

 313-316(1941). 



