DIETARY TRIGLYCERIDES AND PLASMA-BILIARY LIPID BALANCE

血清胆固醇（CHL）升高与以下因素有因果关系： 增加动脉粥样硬化和冠心病的发病率。 饮食中的多不饱和脂肪已经受到了极大的关注， 降低血清CHL和甘油三酯（TG）水平的能力。 研究表明，血清CHL的降低至少部分是由于 增加CHL分泌到胆汁中，这可能导致 CHL胆结石的发病率增加。 最近的研究在配对狗 表明饮食中的ω-6多不饱和脂肪酸 加速胆结石的形成，但饮食中补充omega-3 脂肪酸实际上降低了胆结石的发病率。 此外，委员会认为， 有一些建议认为， 饮食可影响CHL在胆汁中的转运和溶解度。 的假设 需要测试的是：1）饮食中的多不饱和脂肪会降低血清CHL 部分通过增强胆汁CHL分泌，2）饮食TG可能改变 通过改变胆汁的分子种类， 胆汁脂质的总浓度和/或分泌速率。 目的 这项研究的目的是检查修改类型和 日粮TG和CHL的量对：1）血浆中脂质平衡 和胆汁。 将在血浆脂蛋白中测量脂质浓度 和整个血浆，脂质浓度和分泌率将被 在胆汁中测量。 两个隔间的改建将 相关的 2)胆汁携带CHL的能力。 胆囊和 混合胶束将被分离，脂质组成的改变 以及CHL一水合物发生率的变化 将注意到胆汁中的晶体。 3)肝脏的核心作用 维持血浆和胆汁之间的脂质平衡。 肝脏水平 脂质将与在小鼠中相应脂质的水平进行比较。 血浆和胆汁。 测定CHL代谢的肝酶 (acyl CoA-CHL酰基转移酶、HMG CoA还原酶和CHL 7-α 羟化酶），和北方印迹杂交将用于定量 最后两种酶的肝脏mRNA水平。

Elevations in serum cholesterol (CHL) are causally related to an increased incidence of atherosclerosis and coronary heart disease. Dietary poly-unsaturated fats have received a great deal of attention for their ability to decrease levels of serum CHL and triglycerides (TG). Studies suggest that the reduction in serum CHL is due at least in part to an increased secretion of CHL into bile, and this could lead to an increased incidence of CHL gallstones. Recent studies in the paired dog suggest that dietary omega-6 polyunsaturated fatty acids do in fact accelerate gallstone formation, but dietary supplementation with omega-3 fatty acids actually decreases the incidence of gallstones. Furthermore, there has been some suggestion that modification of biliary lipids by diet may influence CHL transport and solubility in bile. The hypotheses to be tested are that 1) dietary polyunsaturated fats reduce serum CHL in part by enhancing biliary CHL secretion and 2) dietary TGs may alter the CHL-carrying capacity of bile by altering the molecular species, total concentrations, and/or secretion rates of biliary lipids. The aim of this study is to examine the effect of modifying both the type and amount of dietary TG and CHL on: 1) The balance of lipids between plasma and bile. Lipid concentrations will be measured in plasma lipoproteins and whole plasma, and lipid concentrations and secretion rates will be measured in bile. Alterations in the two compartments will be correlated. 2) The CHL-carrying capacity of bile. Biliary vesicles and mixed micelles will be separated, and alterations in lipid composition of the particles as well as changes in the incidence of CHL monohydrate crystals in bile will be noted. 3) The central role of the liver in maintaining the lipid balance between plasma and bile. Levels of hepatic lipids will be compared to the levels of the corresponding lipids in plasma and bile. The hepatic enzymes of CHL metabolism will be assayed (acyl CoA-CHL acyl transferase, HMG CoA reductase, and CHL 7-alpha hydroxylase), and Northern blot hybridization will be used to quantitate the levels of hepatic mRNA for the last two enzymes.