Effect of Vitamin D on Prothrombin Deficiency in the Rat

Abstract

It has been reported 1 that the prothrombin deficiency produced in rats by a diet containing 20% mineral oil was corrected by vitamin K, and definitely improved by vitamin D administration. Previously, Smith and coworkers 2 had reported that vitamin D failed to improve the prothrombin deficiency in a biliary fistula dog, and Greaves 3 stated that massive doses of D subcutaneously were without benefit in biliary fistula rats. However, vitamin D has been shown to be of value in treating the bleeding tendency in clinical jaundice. 4 In view of these conflicting reports, we have further investigated the effect of vitamin D on prothrombin deficiency in the rat.

A prothrombin deficiency was produced in 36 normal rats by means of the diet described by Eliot. Isaacs and Ivy 1 (Table I, Group 1). Quick's method 5 for the estimation of prothrombin was used. After 29-52 days on the diet, the prothrombin time was prolonged from an average normal of 17.6 seconds to a mean of 59.7 seconds.

Eighteen rats whose prothrombin times had been increased by the diet from a normal average of 18.0 seconds to 53.4 seconds were given 500 units of vitamin D∗ subcutaneously. One week later the average prothrombin time of the group was 55.4 seconds (Table I, Group 2). There is no significant difference between the average values before and after treatment with vitamin D. Individually, 5 of the 18 appeared significantly improved. Ten of these rats were then given an additional dose of 1000 units of vitamin D subcutaneously (Table I, Group 3). One week later their average prothrombin time was 71.8 seconds compared to 41.2 seconds before the second dose was given. Again in this group, vitamin D failed to improve the prothrombin deficiency.