Peroxisomes and Essential Fatty Acid Deficiency.

Abstract

The effect of dietary essential fatty acid (EFA) deficiency on the lipid composition of peroxisomal extracts was studied in Wistar rats. After 21 days of EFA deficiency, no difference was noted in protein levels, but a significant change had occurred in the level of phospholipids and fatty acid composition of phospholipids. In EFA-deficient rat peroxisomes, phosphatidylcholine and phosphatidylinositol were both significantly higher than in controls. This alteration was more marked in peroxisomes than in microsomes. The peroxisomal fatty acid composition was markedly affected as well. In EFA-deficient rats, linoleic (18:2 n-6), arachidonic (C20:4 n-6), and docosahexaenoic (C22:6 n-3) acids were lower whereas oleic (C18:1 n-9), octadecenoic (C18:1 n-7), and eicosatrienoic (C20:3 n-9) acids were higher than in controls. This alteration was also more prominent in the peroxisomal than the microsomal extracts. Catalase activity was weakly reduced, whereas dihydroxyacetone-phosphate acyltransferase activity was strongly increased in EFA-deficient rats. We conclude that the composition of phospholipids and fatty acids may be a factor contributing to peroxisome function and that a diet poor in essential fatty acids or defective unsaturated fatty acid metabolism could amplify peroxisomal dysfunction of genetic origin.