The Failure of Dinitrophenol to Influence the Vitamin B Requirement *

The studies of Cowgill and his associates2 3 indicate clearly that the metabolic rate is one factor determining the organism's requirement for vitamin B. Increase of this factor by the administration of thyroid7 and by means of forced exercise4 has been found to be associated with a rise in the vitamin B requirement. As an extension of this work it was deemed desirable to ascertain the effect, if any, of fever on the need for vitamin B, particularly so because fever is a feature common to so many different clinical conditions. As a means of raising the temperature and metabolic rate artificially, the drug alpha dinitrophenol appeared to be an ideal agent. Animal experiments by Mayer, cited by Perkins'", and more recently by Magne, Mayer and Plantefol8, and Tainter and Cutting", have shown that the action of this compound is to increase cellular oxidation, with fever appearing secondarily when the rate of oxidation is increased so greatly as to overtax the temperature-regulating mechanisms of the body. It is possible to administer doses of 5 to 10 mgm. per kg. of body weight daily to dogs or rats without recognizable toxic effects. By utilizing the methods already devised in this laboratory for determining the vitamin B requirement of these animals, a comparison was made of this requirement under normal conditions and when the animals were receiving daily doses of the drug.