de Silva Pujitha P, Agarwal-Mawal Alka, Davis Phillip J, Cheema Sukhinder Kaur
Department of Biochemistry, Memorial University of Newfoundland, St, John's, NL, A1B 3X9 Canada.
Nutr Metab (Lond). 2005 Mar 11;2(1):8. doi: 10.1186/1743-7075-2-8.
Cholesterol ester transfer protein (CETP) plays a major role in regulating the levels of LDL- and HDL-cholesterol. We previously observed a fish-oil-induced elevation of low-density lipoprotein (LDL)-and very-low-density lipoprotein (VLDL)-cholesterol concentrations and a decrease in high-density lipoprotein (HDL)-cholesterol concentration in F1B hamsters. The molecular mechanism/s by which fish oil induces hyperlipidaemic effect was investigated in this study. We examined whether the effects of dietary fish oil on plasma lipoprotein concentrations are due to fish-oil-induced alterations in plasma CETP activity. MIX diet, a diet supplemented with a mixture of lard and safflower oil, was used as the control diet. RESULTS: We found that fish oil feeding in hamsters reduced CETP mass as well as CETP activity. Increasing the dietary fat level of fish-oil from 5% to 20% (w/w) led to a further decrease in CETP mass. Supplementation with dietary cholesterol increased both CETP mass and CETP activity in fish-oil and MIX-diet fed hamsters. However, there was no correlation between CETP mass as well as CETP activity and LDL-cholesterol concentrations. CONCLUSION: These findings suggest that cholesterol ester transfer between HDL and LDL is not likely to play a major role in determining fish-oil-induced changes in LDL- and HDL-cholesterol concentrations in F1B hamsters. A possible role of reduced clearance of LDL-particles as well as dietary fat level and dietary cholesterol dependent changes in LDL-lipid composition have been discussed.
胆固醇酯转运蛋白（CETP）在调节低密度脂蛋白（LDL）和高密度脂蛋白（HDL）胆固醇水平方面发挥着主要作用。我们之前观察到鱼油可使F1B仓鼠的低密度脂蛋白（LDL）和极低密度脂蛋白（VLDL）胆固醇浓度升高，高密度脂蛋白（HDL）胆固醇浓度降低。本研究探讨了鱼油诱导高脂血症效应的分子机制。我们研究了膳食鱼油对血浆脂蛋白浓度的影响是否是由于鱼油诱导的血浆CETP活性改变所致。将添加猪油和红花油混合物的MIX饮食用作对照饮食。结果：我们发现给仓鼠喂食鱼油会降低CETP质量以及CETP活性。将鱼油的膳食脂肪水平从5%提高到20%（w/w）会导致CETP质量进一步降低。在喂食鱼油和MIX饮食的仓鼠中，补充膳食胆固醇会增加CETP质量和CETP活性。然而，CETP质量以及CETP活性与LDL胆固醇浓度之间没有相关性。结论：这些发现表明，HDL和LDL之间的胆固醇酯转运不太可能在决定鱼油诱导的F1B仓鼠LDL和HDL胆固醇浓度变化中起主要作用。文中讨论了LDL颗粒清除减少以及膳食脂肪水平和膳食胆固醇依赖性LDL脂质组成变化的可能作用。
