The Composition of Liver Vitamin a Ester and the Synthesis of Vitamin a Ester by Liver Microsomes.

The liver is capable of storing large quantities of vitamin A in ester form (1). However, some uncertainty still exists concerning both the composition of liver vit,amin A ester and the ability of the liver to esterify vitamin A. Vitamin A palmitate was isolated from fish liver many years ago (a), and recently it has been suggested that this ester is the principal if not exclusive (3, 4) ester of vitamin A stored by the liver. Previous attempts to demonstrate the esterification of vitamin A by preparations of liver tissue have not been successful (5, 6). However, the isolated, perfused liver is able to synthesize vitamin A ester (7, 8). In the present report the fatty acid composition of vitamin A ester isolated from the liver of the calf, sheep, rabbit, man, rat, frog, trout, and cat is described, and evidence is provided that the synthesis of vitamin A ester in the liver occurs in the microsomes.