DESATURATION OF ESSENTIAL FATTY ACIDS USING STABLE ISOTOPE GC-MS

已经发现，长期的乙醇消费会降低 多不饱和脂肪酸，尤其是血浆中的20：4 n6和22：6 n3 脂蛋白、红细胞、肝脏、大脑和灵长类动物的视网膜 以及维持低EFA饮食的猫（在中枢神经系统中， 22：6 n3是下降的主要脂肪酸）。 这可能是由于 抑制乙醇引起去饱和和/或脂质增加 过氧化产物如醛（4-羟基-壬烯醛和4-羟基-壬烯醛）， 己烯醛）和异前列烷。 必需脂肪酸（EFA），亚油酸 (18：2n 6）和亚麻酸酯（18：3 n3），被去饱和和拉长， 花生四烯酸（20：4 N6）和二十二碳六烯酸（22：6 N3）。 一 稳定同位素气相色谱-质谱（GC-MS）法， 用于检测乙醇对聚- 不饱和脂肪酸在体内。 正在使用其他GC-MS程序 研究4-羟基-烯醛和异前列烷的产生 在组织中。 低EFA饮食的灵长类动物一直在消耗乙醇（11-15%的 他们的卡路里）每天三年已经发展出显着的肝脏 病理 沿着适量的脂肪沉积和肝脏 在炎症中，胶原蛋白水平显着增加， 在窦状隙和周围静脉区域内。 的水平 4-羟基-烯醛和异前列烷也在肝脏中升高 动物饮酒的证据 20：4 n6和22：6 n3水平下降 在血浆脂蛋白、红细胞和肝磷脂中。 在 大脑中22：6 n3的水平显着降低， 22：5n6 体内EFA代谢研究表明， 18：3 n3或18：2n 6进入血浆的量在食用18：3 n3或18：2n 6的动物中大致相同 酒精作为对照。 灵长类动物饮酒增加了 视网膜电图中b波潜伏期延长和b波振幅降低 与对照相比。

Prolonged ethanol consumption has been found to lower the levels of polyunsaturated fatty acids especially, 20:4n6 and 22:6n3, in plasma lipoproteins, erythrocytes, livers, brains, and the retinas of primates and felines maintained on low EFA diets (in the central nervous system, 22:6n3 is the principal fatty acid which declined). This may be due to the inhibition of desaturation by ethanol and/or to an increase in lipid peroxidation products such as aldehydes (4-hydroxy-nonenal and 4-hydroxy- hexenal) and isoprostanes. The essential fatty acids (EFA), linoleate (18:2n6) and linolenate (18:3n3), are desaturated and elongated to arachidonate (20:4n6) and docosahexaenoate (22:6n3), respectively. A stable isotope gas chromatography-mass spectrometry (GC-MS) method is being used to examine the effects of ethanol on the production of poly- unsaturated fatty acids in vivo. Other GC-MS procedures are being used to investigate the production of 4-hydroxy-alkenals and the isoprostanes in tissues. Primates on a low EFA diet that have been consuming ethanol (11-15% of their calories) daily for three years have developed significant liver pathology. Along with moderate amounts of fat deposition and liver inflammation there are notable increases in the collagen levels both within the sinusoids and surrounding venal regions. The levels of the 4-hydroxy-alkenals and the isoprostanes were also elevated in the liver of animals consuming alcohol. The levels of 20:4n6 and 22:6n3 decreased in plasma lipoproteins, erythrocytes, and liver phospholipids. In the brains there were dramatically lower levels of 22:6n3 and higher levels of 22:5n6. In vivo EFA metabolism studies indicated that the uptake of 18:3n3 or 18:2n6 into the plasma was about the same in animals consuming alcohol as the controls. Primates consuming alcohol had increased a- and b-wave latencies and lower b-wave amplitudes in their electroretinograms compared to controls.