Rat Acrodynia and the Essential Fatty Acids

Abstract

On a basal diet of purified casein, glucose and salts, supplemented with carotene, calciferol, synthetic B₁ and riboflavin, rats developed skin lesions in 4 to 5 weeks; an acute dermatitis when restricted to the basal diet; and a chronic form, ‘rat-acrodynia,’ when given fat supplements at subcurative levels. Complete healing of either the acute or chronic form was obtained by the administration of peanut oil or wheat germ oil. Cured animals maintained themselves free from all symptoms so long as the fat supplements were continued or until the end of the survival period, which was usually several months. Aeration or ultraviolet radiations did not destroy the activity in peanut oil. It was resident in the fatty acid fraction. Cures were produced with 1/2 drop of wheat germ oil, corn oil or Wesson oil, 10 drops of coconut oil or 25 drops of butterfat. The lesions were not prevented nor cured with hydrogenated coconut oil. The unsaponifiable fraction from wheat germ oil was devoid of potency; the ethyl esters prepared from the soap fraction contained all of the activity. When the unsaturated fatty acids were fractionally crystallized from acetone, the highest potency was obtained with the fraction separating between -50 and -75°C. One-half drop of ethyl linoleate (Rollett, '09) per day cured the dermatitis completely. The ethyl ester of elaidinized linoleic acid was found to be inactive.