Fish Oil Enriched Diet-Induced in vivo Lipid Peroxidation and Increased Excretion of Urinary Lipophilic Lipid Metabolites in Rats

Peroxidative stimuli mediated by high polyunsaturated fatty acid administration in rats induced in vivo lipid peroxidation and resulted in increased urinary excretion of a number of lipophilic aldehydes and related carbonyl compounds. These secondary lipid peroxiation products, measured as 2, 4-dinitrophenylhydrazine deritives, were detected and identified by the newly developed HPLC method. The identified urinary lipophilic nonpolar aldehydes and related carbonyl compounds were butanal, butan-2-one, pentan-2-one, hexanal, hex-2-enal, hepta-2, 4-dienal, hept-2-enal, octanal, and oct-2-enal. Lipophilic polar aldehydes such as 4-hydroxyhex-2-enal and 4-hydroxyoct-2-enal were also identified. A polyunsaturated fatty acid diet containing n-3 fatty acids generally caused high levels of urinary excretion of lipophilic aldehydes and related carbonyl compounds in rats than a normal diet. Significantly increased secondary lipid peroxidation products were hexanal, hepta-2, 4-dienal, octanal, 4-hydroxyhex-2-exal, 4-hydroxyoct-2-enal, and a number of unidentified compunds.