//4 XII. VITAMINS K 



vitamin K synthesis in the gastrointestinal tract has been discussed earUer 

 (see page 759). 



According to Lockhart, Sherman, and Harris, ''^^ the administration to 

 rats of a diet high in triglycerides containing dihydroxystearic acid pro- 

 duces a condition of hypoprothrombinemia. Since the intestinal bacteria 

 are qualitatively and quantitatively normal without producing any vita- 

 min K, it is assumed that the vitamin-synthesizing enzyme systems in the 

 bacteria may be blocked.'"^ One result which is difficult to interpret in 

 line with the thesis that vitamin K is synthesized in the gut by the intestinal 

 bacteria is that of Luckey ei al.,^^^ who worked Avith germ-free rats. The 

 animals which were maintained in such a manner that the gastrointestinal 

 tract remained sterile did not develop any abnormality in the blood- 

 clotting mechanism when fed on a diet devoid of vitamin K. However, 

 none of the vitamin was found in the liver, feces, bladder contents, or cecal 

 contents. 



c. Reduced Absorption of Vitamin K. Any condition which reduces the 

 ability of the intestine to absorb vitamin K will tend to result in a vitamin 

 K deficienc3^ Thus, one reason why poultry are readily susceptible to 

 vitamin K-deficiency is that they have a short large intestine, which is 

 believed to be inadequate for the absorjjtion of bacterially-produced vita- 

 min K.^* The lower colon of mammals is probably also incapable of 

 absorbing vitamm K effectively, even in the presence of bile; this is shown 

 by the fact that retention enemas cannot supply vitamm K to the or- 

 ganism. ^"^ Also Greaves*'^ demonstrated that one could produce a vitamin 

 K deficiency in rats if the bile duct was diverted into the colon. On the 

 other hand, the cecum has been reported to be an imporant site of bacterial 

 synthesis of vitamin K." Dam and Glavind^'" reported that the clotting 

 time was prolonged in chickens as a result of ligation of the bile duct. 



The absence of bile from the gut prevents the absorption of exogenous 

 as well as of endogenous vitamin K. This was discussed at some length 

 in an earlier section. The condition can be corrected by the administra- 

 tion of bile or of bile salts. Water-soluble preparations of vitamin K 

 are effectively absorbed when given orally in the absence of bile.''"-^" 



206 E. E. Lockhart, H. Sherman, and R. S. Harris, Science, 96, 542-543 (1942\ 

 20' G. Nightingale, E. E. Lockhart, and R. S. Harris, Arch. Biochem., 12, 381-387 

 (1947). 



208 T. D. Luckoy, J. R. Pleasants, M Wagner, H. A. Gordon, and J. A. Reyniers, /. 

 Nutrition, 57, 169-182 (1955). 



209 H. P. Smith, S. E. Ziffern, C. A. Owen, G. R. Hoffman, and J. E. Flynn, J. Iowa 

 State Med. Soc, 29, 377-384 (1939). 



210 H. Dam and J. Glavind, Z. Vitaminforsch., 10, 71-79 (1940). 



2" H. P. Smith and C. A. Owen, J. Biol. Chem., 134, 783-784 (1940). 



