![Sample our Medicine, Dentistry, Nursing & Allied Health journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/5944/TOC-Subject-Sample-2021-Medicine-Dentistry-Nursing-Allied-Health.jpg"})
Summary
The effect of dietary lipid content on the fatty acid composition of the liver endoplasmic reticulum and the effect of the fatty acid composition on the oxidative metabolism of Benzo (a) Pyrene (BP) in the liver endoplasmic reticulum were studied in rats. The rate of oxidative metabolism of BP was found to be markedly dependent on the percentage of polyunsaturated fatty acids incorporated into the membrane of the endoplasmic reticulum. Diets containing 10% lard or 10% corn oil caused the incorporation of 10.3% and 25.1% linoleicacid (C18: 2) and oxidation rates of 68.3 and 113.8 nmol 3‐hydroxybenzo (a) pyrene/30 min/g liver, respectively. Diets containing 10% herring oil caused incorporation of only 5.1 % C18: 2 but also 27.2% ω3 unsaturated fatty acids, including 8.7% eicosapentaenoic acid (C20: 5) and 17.0% doco‐sahexaenoic acid (C22: 6) and caused a high oxidation rate (145.8 nmol) 3‐hydroxybenzo (a) pyrene/30 min/g liver.
Phenobarbitone (100 mg/kg) and 20‐methyl‐cholanthrene (20 mg/kg) strongly enhanced the oxidation rate of BP in groups of rats fed a herring oil diet and induction was much greater in the group fed an irradiated diet than in the group fed an untreated herring oil diet. Irradiation with 400 krad caused destruction of the major proportion of the polyunsaturated fatty acids in herring oil, incorporation of a smaller quantity of ω3 unsaturated acids into the endoplasmic reticulum, and a decrease in the rate of oxidation to 122.5 nmol 3‐hydroxybenzo (a) pyrene/30 min/g liver.
The antioxidant 2,6‐di‐tert‐butyl‐4 methylphenol, BHT, (0.01 %) added to irradiated herring oil diets strongly reduced the inductive effect of phenobarbitone. This effect may therefore be caused by the presence of lipid peroxides in the irradiated diet.
It is concluded that dietary C18: 2 is an important factor in the regulation of the rate of oxidative metabolism of BP in the liver endoplasmic reticulum, but C18: 2 may be effectively replaced by dietary C20: 5 and C22: 6. Oxidation of BP is regulated by changes in the fatty acid composition of the membranes of the liver endoplasmic reticulum.