Effectiveness of Arachidonic Acid in Curing “Fat Deficiency” Disease. ∗

Abstract

The earlier work by Evans and Burr, 1 by Burr and collaborators, 2 , 3 and by Evans and Lepkovsky 4 has definitely shown that the rat cannot maintain growth and well-being on diets rigidly devoid of fat, but invariably develops a characteristic deficiency disease. The vital need of the animal is not, however, as the same investigators have demonstrated, for fat in general but for certain unsaturated fatty acids. Of these, only linoleic and linolenic acids have so far proved effective in curing this specific deficiency, whereas oleic and alpha-eleostearic acids have been found inactive. Now, whether the 2 first-mentioned acids are the only ones capable of satisfying the need of the body for unsaturated fatty acids or whether other fatty acids with the same curative effect exist is naturally a question of great interest and of considerable theoretical significance.

In the following, the results of some experiments with arachidonic acid are reported. This acid has been tested once before by Burr, Burr and Miller, 3 who found that an addition of methyl arachidonate as 10% to a mixture of equal parts of methyl linoleate and methyl linolenate slightly decreased the curative effect of the original mixture. This result did not, however, seem quite plausible, even to the above mentioned investigators, and it was felt by us that further tests with arachidonic acid were urgently needed.

Young female rats immediately after weaning were placed on a fat-low, casein-sucrose-salt diet supplemented with yeast and the non-saponifiable fractions from cod liver oil and wheat germ oil. When growth had ceased and the animals had reached a “plateau”, they were deemed ready for tests. They were not used, however, before they had shown a constant or slightly declining weight over a period of at least 30 days.