Absorption of 2-Methyl-1,4-Naphthoquinone and Phthiocol by Bile Fistula Rats ∗

Abstract

It is now well established that deoxycholic acid is necessary for the absorption of vitamin K. The fact that certain water soluble compounds possess vitamin K activity has raised the question as to whether or not these substances are absorbed from the intestinal tract in the absence of bile. Smith and Owen 1 have shown that oral administration of 4-amino-2-methyl-1-naphthol to patients suffering from chronic obstructive jaundice led to an increase in the level of prothrombin. Similar results were reported by Warner and Flynn 2 on administration of the potassium salt of the disulfuric acid ester of 2-methyl-1,4-naphtho-hydroquinone to vitamin K depleted bile-obstructed rats. The present experiments are in harmony with these two observations, although the compounds used and the experimental technic employed were somewhat different.

Choledochocolonostomized rats were maintained on a low vitamin K diet and were kept in cages with wide mesh screen bottoms to prevent their having access to their feces. Three to 6 weeks following the operation there was a decrease in the prothrombin content of the blood. For the prothrombin estimations, blood was obtained by heart puncture. In this connection it should be pointed out that it is not feasible to obtain blood in this manner when the prothrombin levels are much lower than about 50%, due to the possibility of hemorrhage. The prothrombin levels were estimated according to the method of Almquist and Klose, 3 modified so that only 0.5 cc of blood was required. When the prothrombin level had fallen to about 50%, the compound under test was administered orally. The data are given in Table I.

The data indicate that both phthiocol and 2-methyl-1,4-naphthoquinone are absorbed from the intestinal tract of bile fistula rats, and that deoxycholic acid is not necessary to insure the absorption of these compounds.