780 XII. VITAMINS K 



The vitamin K was found in the egg yolk but not in the white of the egg. 

 It is suggested that the increase in prothrombin content, which may occur 

 in chick blood for several days after hatching, may result from the assimila- 

 tion of the last of the vitamin K stores from the yolk.^^^ 



When the amount of vitamin Iv required was based upon the quantity 

 necessary to reduce the blood-clotting time to ten minutes or less, eighteen 

 hours after dosage, several groups of workers^^-^^^-^^^ reported a figure of 

 1 jug. The quantity of methylnaphthoquinone that is needed to effect a 

 similar improvement has been given as 0.3 ng. by Fieser et al.^^ Values 

 employing the six-hour assay were 1.5 jug. for vitamin Ki and 0.5 /xg. for 

 menadione. ^^ 



Different procedures have also been employed. Thus, Quick and Ste- 

 fanini^^* reported that 5 jug- of menadione would bring the level of pro- 

 thrombin in the chick from 10% of normal to normal within four hours. 

 Tidrick and associates^^^ observed a complete recovery of prothrombin in 

 six hours when 16 ^g- were given, and a 50% recovery with 8 jug- of mena- 

 dione. 



More precise information on the daily requirements for vitamin K in 

 chickens can be obtained by determination of the amount necessary to 

 maintain a normal blood-clotting time. When the assays were continued 

 for five days or more, 2 jug- of menadione daily were found by a number of 

 groups of investigators^^'* ■"^^■-"•-^^ to be sufficient. 



(2) Requirement for Other Animals 



Flynn and Warner-^^ reported that two intraperitoneal doses of 1000 

 jug. of phthiocol, or two daily doses of 2 /xg. of menadione are necessary to 

 bring about a moderate recovery in bile-fistula rats. Warner and Flynn'^" 

 observed that 8 )ug. of the disulfuric acid ester of 3-methyl-l,4-naphtho- 

 quinone are required daily to cure depleted rats. In the case of dogs ren- 

 dered vitamin K-deficient by cholecystonephrostomy, Collentine and 

 Quick^^" noted that the intravenous injection of 10 )ug. of phytylmenadione 

 (vitamin Ki)/kg. body weight restored the clotting time of the blood to 



=63 F. W. Stamler, R. T. Tidrick, and E. D. Warner, /. NutrUion, 26, 95-103 (1943). 



254 E. Fernholz, S. Ansbacher, and H. B. MacPhillamy, ,/. Am. Chem. Soc, 62, 430-432 

 (1940). 



258 A. D. Emmott, R. A. Brown, and (). Kamm, J. Biol. Chem., 132, 407-408 (1940). 



^ R. T. Tidrick, F. T. Joyce, and H. P. Smith, Proc. Soc. Exptl. Biol. Med., 42, 853- 

 857(1939). 



2" H. J. Almqnist and A. A. Klose, ./. Biol. Chem., 130, 787-789 (1939\ 



258 H. J. Almqnist and A. A. Klose, Proc. Soc. Expll. Biol. Med., 45, 55-59 (1940). 



259 J. E. Flynn and E. D. Warner, Proc. Soc. Exptl. Biol. Med., 43, 190-194 (1940). 



