Metabolic relationships between fatty alcohol and fatty acid in the liver of Squalus acanthias

The high speed supernatant fraction of a homogenate of Squalus acanthias L. liver catalyses the oxidation of oleyl alcohol to oleic acid by an NAD-dependent process. Reduction of fatty acid to fatty alcohol could not be demonstrated. Liver lipids of S. acanthias contain about 60 and 40% of triglycerides and diacyl glyceryl ethers, respectively, with only traces of wax esters. Serum lipids contain 28, 15 and 26% of triglycerides, diacyl glyceryl ethers and wax esters, respectively. Cell-free fractions of S. acanthias liver catalyse the formation of wax esters by an ATP¹-dependent process. The bulk of wax ester synthesis occurs in the high-speed supernatant fraction of liver. The rate of formation of the ester bond in wax esters is comparable to the rate of synthesis of ester bonds in triglycerides, and greatly exceeds the rate of formation of the ether bond in diacyl glyceryl ethers. Results are discussed in terms of possible factors controlling the levels of neutral lipids in S. acanthias.