Yang L Y, Kuksis A, Myher J J
Department of Biochemistry, University of Toronto, Canada.
Lipids. 1991 Oct;26(10):806-18. doi: 10.1007/BF02536162.
This study tests the hypothesis that the rat chylomicrons are assembled and released into lymph similarly regardless of the site (rough or smooth endoplasmic reticulum) or pathway (phosphatidic acid or monoacylglycerol) of triacylglycerol biosynthesis. For this purpose we determined the lipid class, fatty acid and molecular species composition of the choline, ethanolamine, inositol and serine phospholipids of lymph chylomicrons during absorption of menhaden, mustard-seed and corn oil (monoacylglycerol pathway) or the corresponding fatty acid methyl or ethyl esters (phosphatidic acid pathway). The dietary fatty acids were found to be incorporated to various extents into different phospholipid classes, the proportions of which were not affected by the nature of the dietary fat. The chylomicron phospholipids contained 80-82% choline, 8% ethanolamine and 2.5% inositol glycerophospholipids, and much smaller amounts of serine and other minor phospholipids. Administration of a meal of each dietary fat resulted in a retention of approximately 50% endogenous fatty acids in the major glycerophospholipids of the chylomicrons. A minimum of 50% of the molecular species of the choline and ethanolamine glycerophospholipids contained at least one exogenous fatty acid. No significant discrepancies were found in the fatty acid and molecular species composition of the glycerophospholipids between chylomicrons from the oil and corresponding ester feeding. It is concluded that the chylomicrons arising from the monoacylglycerol (oil feeding) and the phosphatidic acid (ester feeding) pathways of triacylglycerol biosynthesis become enveloped in surfactant monolayers containing qualitatively and quantitatively identical classes and molecular species of phospholipids.
无论三酰甘油生物合成的位点（糙面或光面内质网）或途径（磷脂酸或单酰甘油）如何，大鼠乳糜微粒都是以相似的方式组装并释放到淋巴中的。为此，我们测定了在吸收鲱鱼油、芥花籽油和玉米油（单酰甘油途径）或相应的脂肪酸甲酯或乙酯（磷脂酸途径）期间，淋巴乳糜微粒中胆碱、乙醇胺、肌醇和丝氨酸磷脂的脂质类别、脂肪酸和分子种类组成。发现膳食脂肪酸以不同程度掺入不同的磷脂类别中，其比例不受膳食脂肪性质的影响。乳糜微粒磷脂含有80 - 82%的胆碱、8%的乙醇胺和2.5%的肌醇甘油磷脂，以及少量的丝氨酸和其他次要磷脂。给予每一种膳食脂肪餐会使大约50%的内源性脂肪酸保留在乳糜微粒的主要甘油磷脂中。胆碱和乙醇胺甘油磷脂的分子种类中至少有50%含有至少一种外源性脂肪酸。在油喂养和相应酯喂养产生的乳糜微粒之间，甘油磷脂的脂肪酸和分子种类组成未发现显著差异。结论是，由三酰甘油生物合成的单酰甘油（油喂养）和磷脂酸（酯喂养）途径产生的乳糜微粒被包裹在含有定性和定量相同类别的磷脂和分子种类的表面活性剂单分子层中。
