Metabolism and function of plasma lipoprotein plasmalogen in fish

研究了鱼血浆脂蛋白中磷脂和高度不饱和脂肪酸的代谢。在几种条件下分析了鱼血浆中葡萄糖、三酰甘油、酯化胆固醇、游离胆固醇和酮体的含量。分析了磷脂和三酰甘油的脂肪酸组成以及缩醛的醛组成。采用密度梯度超速离心法分离富含甘油三酯脂蛋白、低密度脂蛋白和高密度脂蛋白，并采用琼脂糖凝胶电泳进行分离。与哺乳动物相比，鱼类的脂蛋白中含有丰富的磷脂。用高效液相色谱法测定血浆脂蛋白中磷脂主要为磷脂酰胆碱和鞘磷脂。血浆脂蛋白磷脂组成与血细胞中包括的其他器官有很大不同。但是，由于养殖条件的改变，不能清楚地反映出血浆酶原组成和含量的变化。以放射性脂肪酸为原料制备长链醇，并将其用于烯基醚类脂质的代谢研究。结果表明，血浆酶原是在肝脏中生物合成的.从放射性磷脂制备脂质体，并检查磷脂在脂蛋白之间的转移。同时测定与脂代谢有关的血浆LCAT和CETP活性。认为富含三酰甘油的脂蛋白从肝脏流出和磷脂从外周组织的外叶提取可能是血浆中缩醛磷脂的来源。

The phospholipids and highly unsaturated fatty acids metabolism in fish plasma lipoprotein were examined. The contents of glucose, triacylglycerol, esterified cholesterol, free cholesterol and ketone body in fish plasma were analyzed under several conditions. The fatty acid compositions of phospholipid and triacyl-glycerol and the aldehyde composition of plasmalogen were analyzed. Triacylglycerol-rich lipoprotein, low-density lipoprotein and high-density lipoprotein were divided by density-gradient ultra centrifugation and also separated by agarose gel electrophoresis. In comparison with mammals, phospholipids were abundantly detected in the lipoprotein of the fishes. It was clarified that phospholipid in the blood plasma lipoprotein was mainly phosphatidylcholine and sphingomyelin by high performance liquid chromatography. The plasma lipoprotein phospholipid composition is greatly different from other organs that include in blood cells. However, the change of plasmalogen composition and content could not be clearly recognized by the change of the breeding condition. The long chain alcohol was prepared from radioactive fatty acid, and it was used for metabolism research of the alkenyl ether lipids. It was indicated the plasmalogen was bio- synthesized in the liver. The liposome was prepared from the radioactive phospholipid, and the transfer of the phospholipid between lipoprotein was examined. The activities of plasma LCAT and CETP that concerning lipid metabolism were also examined. It was considered that the efflux of the triacylglycerol-rich lipoprotein from the liver and the extraction of phospholipids from the outer leaflet of peripheral tissues might be the origin of plasmalogen in plasma.