TISSUE LIPID-PEROXIDATION AND SERUM-LIPOPROTEINS IN HAMSTERS ARE AFFECTED BY DIETARY-PROTEIN COMPOSITION

In the present study, the relationship between hyperlipidemia induced by ingestion of animal protein and tissue lipid peroxidation was exami ned. Male Golden Syrian hamsters were fed for 27 days cholesterol-enri ched (0.088 wt%) semi-purified diets having either 15 wt% casein (GAS) or egg white (EGG) as the protein source. Hamsters fed the CAS diet s howed higher concentrations of serum total cholesterol and triglycerid es as compared with EGG-fed hamsters. The change in total serum choles terol and triglyceride concentrations over the 27-day dietary period w as significantly greater in the GAS-fed hamsters than in the EGG group . Lipid peroxidation as measured by lipid hydroperoxides (LPO) was inc reased in the serum and liver of GAS-fed relative to the EGG-fed hamst ers. Liver concentrations of thiobarbituric acid reactive substances, another index of lipid peroxidation, were unaffected by dietary protei n composition. When the two dietary treatments were grouped together, a positive correlation was observed between serum LPO and serum apolip oprotein B (r=0.52; P < 0.05) and a negative correlation was noted bet ween serum LPO and the serum apolipoprotein A-I to apolipoprotein B ra tio (r=.0.84; P < 0.005). This study supports the hypothesis that the amino acid composition of proteins can modulate tissue lipid peroxidat ion concentrations in the Syrian hamster and that an oxidative challen ge induced by GAS-based diets could play a role in this dietary-induce d hyperlipidemia. Copyright (C) 1997 Elsevier Science Inc.