BIOSYNTHESIS OF WAX ESTERS IN FISH . REDUCTION OF FATTY ACIDS AND OXIDATION OF ALCOHOLS

Biosynthesis of wax esters in roe of gouramis (Trichogaster) was studied. When methyl esters of 14C-labeled palmitic, oleic, linoleic, and other fatty acids were fed to adult female gouramis, between 20 and 60% of the radioactivity was recovered in the total lipids of the fish and approximately two-thirds of that was in roe wax esters. Analyses of the constituents of the wax esters showed that the saturated and monounsaturated esters had been extensively reduced to the respective alcohols. Less reduction occurred with more highly unsaturated esters, but some alcohol was formed even from docosahexaenoate. Palmitic acid was reduced as efficiently as its methyl ester. When labeled palmityl or oleyl alcohol was fed, the incorporation was similar to that from the corresponding methyl esters. The equilibria of alcohol and acid of these chain structures also were the same after feeding alcohols as after feeding methyl esters. The reduction and oxidation of carboxyl and alcohol groups seem to apply to all common lipid chains. Elongation and desaturation as well as degradation and resynthesis of the chains took place only to a minor extent. However, [1-14C]acetate was incorporated to 17% in lipids. Most of this radioactivity was in the saturated and monounsaturated alcohols of the roe wax esters. © 1969, American Chemical Society. All rights reserved.