Wood R, Chumbler F, Wiegand R
J Biol Chem. 1977 Mar 25;252(6):1965-70.
Groups of rats bearing Morris minimal deviation hepatoma 7288CTC were fed a fat-free diet supplemented with either 0.5% safflower oil (diet A), 15% safflower oil or free acids (diets Band C), or 15% safflower oil or free safflower fatty acids (diet D) for 4 weeks. A group of normal rats was also fed diet D. Triglycerides, cholesteryl esters, phosphatidylcholines, and phosphatidylethanolamines isolated from livers and hepatomas of animals on each diet were analyzed quantitatively for positional isomers in the cis- and trans-octadecenoate fractions. When sufficient samples could be obtained, the cis- and trans-hexadecenoate fractions were also analyzed. Plasma from normal rats on diet D was analyzed in the same manner. The octadecenoate fractions of all hepatoma and liver lipid classes from animals fed diets A, B, and C were greater than 95% the cis isomers. Trans isomers accounted for approximately 15, 30, 50, and 70% of the octadecenoate fractions isolated from liver triglycerides, cholesteryl esters, phosphatidylcholines, and phosphatidylethanolamines, respectively, of animals fed diet D. In contrast, all hepatoma lipid classes from animals on diet D contained the same approximate percentage of trans isomers (15 to 20%). Oleic and vaccenic acids were the major positional cis-octadecenoate isomers of all liver and hepatoma lipid classes from animals fed diets A, B, and C. The ratios of oleic to vaccenic, unaffected by diets A, B, and C, differed for each lipid class in liver, but the ratios were similar for the two hepatoma neutral lipid classes and for the two phospholipid classes. The cis-octadecenoate fractions from all liver and hepatoma lipid classes of animals fed diet D consisted predominantly of the delta9, delta11, and delta12 isomers. The cis delta10 isomer, which was a major isomer of the diet, was almost excluded from liver, hepatoma, and plasma lipids. The positional isomers of the trans-octadecenoate fractions from liver and hepatoma triglycerides and cholesteryl esters exhibited the same approximate distribution as the trans fatty acids of diet D. In contrast, the 10-trans-octadecenoate, like 10-cis-octadecenoate, was almost excluded from the phospholipids of liver and plasma. Unlike liver, the hepatoma phospholipids contained 10-trans-octadecenoate at approximately half the percentage of neutral lipids. Because diet D contained no hexadecenoic fatty acids, the occurrence of trans-hexadecenoate isomers in liver and plasma lipids indicated a chain shortening process. Predominance of the 8-trans-hexadecenoate isomer indicated a preference of the 10-trans-octadecenoate isomer for chain shortening.
给携带Morris最小偏离肝癌7288CTC的大鼠分组，分别喂食不含脂肪但添加了0.5%红花油的饮食（饮食A）、15%红花油或游离酸的饮食（饮食B和C）、15%红花油或游离红花脂肪酸的饮食（饮食D），持续4周。另一组正常大鼠也喂食饮食D。对每组饮食喂养的动物肝脏和肝癌中分离出的甘油三酯、胆固醇酯、磷脂酰胆碱和磷脂酰乙醇胺进行定量分析，以确定顺式和反式十八碳烯酸部分的位置异构体。当能获得足够样本时，也对顺式和反式十六碳烯酸部分进行分析。以同样方式分析喂食饮食D的正常大鼠的血浆。喂食饮食A、B和C的动物，其所有肝癌和肝脏脂质类别的十八碳烯酸部分中，顺式异构体含量超过95%。反式异构体分别约占喂食饮食D的动物肝脏甘油三酯、胆固醇酯、磷脂酰胆碱和磷脂酰乙醇胺中分离出的十八碳烯酸部分的15%、30%、50%和70%。相比之下，喂食饮食D的动物的所有肝癌脂质类别中反式异构体的百分比大致相同（15%至20%）。油酸和vaccenic酸是喂食饮食A、B和C的动物所有肝脏和肝癌脂质类别的主要顺式十八碳烯酸位置异构体。油酸与vaccenic酸的比例不受饮食A、B和C的影响，在肝脏的每种脂质类别中有所不同，但在两种肝癌中性脂质类别和两种磷脂类别中比例相似。喂食饮食D的动物所有肝脏和肝癌脂质类别的顺式十八碳烯酸部分主要由δ9、δ11和δ12异构体组成。顺式δ10异构体是饮食中的主要异构体，几乎被排除在肝脏、肝癌和血浆脂质之外。肝脏和肝癌甘油三酯及胆固醇酯中反式十八碳烯酸部分的位置异构体与饮食D的反式脂肪酸呈现大致相同的分布。相比之下，10-反式十八碳烯酸与10-顺式十八碳烯酸一样，几乎被排除在肝脏和血浆的磷脂之外。与肝脏不同，肝癌磷脂中10-反式十八碳烯酸的含量约为中性脂质的一半。由于饮食D不含十六碳烯酸，肝脏和血浆脂质中反式十六碳烯酸异构体的出现表明存在链缩短过程。8-反式十六碳烯酸异构体占优势表明10-反式十八碳烯酸异构体更倾向于链缩短。
