Microsomal delta 9, delta 6 and delta 5 desaturase activities and liver membrane fatty acid profiles in alcohol-fed rats.

In experimentally produced alcoholic fatty liver microsomal fatty acid composition was measured using gas chromatography. The results showed an increase in linoleic acid (18:2, n-6) and hexadecaenoic acid (22:6, n-3) and a decrease in arachidonic acid (20:4, n-6) in alcohol-fed rats. Using high performance liquid chromatographic separation of radiolabelled substrate and products, delta 9, delta 6 and delta 5 desaturase enzymes were assayed. The activity of delta 9 and delta 5 desaturase was decreased in alcohol-fed rats and delta 6 desaturase activity was similar in control and alcohol-fed groups. These results indicated there was no causal relationship between desaturase activity and membrane fatty acid changes. Increased amounts of eicosatrienoic acid (20:3, n-9) in rats fed less than 5% fat were observed in both control and alcohol-fed rats. The results indicated that essential fatty acid deficiency was not due to alcohol consumption.