PEROXISOMES AND ESSENTIAL FATTY-ACID DEFICIENCY

The effect of dietary essential fatty acid (EFA) deficiency on the lip id composition of peroxisomal extracts was studied in Wistar rats. Aft er 21 days of EFA deficiency, no difference was noted in protein level s, but a significant change had occurred in the level of phospholipids and fatty acid composition of phospholipids. In EFA-deficient rat per oxisomes, phosphatidylcholine and phosphatidylinositol were both signi ficantly higher than in controls. This alteration was more marked in p eroxisomes 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 we re lower whereas oleic (C18:1 n-9), octadecenoic (C18:1 n-7), and eico satrienoic (C20:3 n-9) acids were higher than in controls. This altera tion was also more prominent in the peroxisomal than the microsomal ex tracts. Catalase activity was weakly reduced, whereas dihydroxyacetone -phosphate acyltransferase activity was strongly increased in EFA-defi cient rats. We conclude that the composition of phospholipids and fatt y acids may be a factor contributing to peroxisome function and that a diet poor in essential fatty acids or defective unsaturated fatty aci d metabolism could amplify peroxisomal dysfunction of genetic origin.