RAPID EFFECTS OF DIETARY FISH-OIL ON PEROXISOMES IN MOUSE-LIVER

We investigated hepatic catalase activity, and morphologic and morphom etric alterations of hepatocellular peroxisomes after catalase cytoche mistry, in mice given a diet supplemented with 10% Beromegan(R), a com mercial fish oil preparation, for up to three days. Fish oil is rich i n docosahexaenoic acid (C22:6 (n-3)) and in eicosapentaenoic acid (20: 5 (n-3)). Hepatic catalase activity showed a gradual increase in mice fed this diet, being significantly increased (136+/-10 U(B)/g liver) a fter three days when compared top controls (85+/-11 U(B)/g liver). Lig ht microscopy indicated an increase in peroxisomal staining and peroxi somal proliferation. The latter observation was confirmed by ultrastru ctural morphometry: number, volume density and surface density of the peroxisomes were more than doubled after a three day diet containing f ish oil. Peroxisomal size was not changed. These alterations are sugge stive for an increased peroxisomal metabolism induced by a diet rich i n poly-unsaturated fatty acids.