Anderson G J, Tso P S, Connor W E
Section of Clinical Nutrition and Lipid Metabolism, Oregon Health Sciences University, Portland 97201.
J Clin Invest. 1994 Jun;93(6):2764-7. doi: 10.1172/JCI117293.
The developing brain obtains polyunsaturated fatty acids from the circulation, but the mechanism and route of delivery of these fatty acids are undetermined. 14C-labeled chylomicrons were prepared by duodenal infusion of [1-14C]16:0, [1-14C]18:2(n-6), [1-14C]18:3(n-3), or [1-14C]22:6(n-3) into adult donor rats, and were individually injected into hepatectomized 2-wk-old suckling rats. After minor correction for trapped blood in the brain, the incorporation of chylomicron fatty acids after 30 min was nearly half that of a co-injected free fatty acid reference. [1-14C]22:6(n-3)-labeled chylomicrons showed an average 65% greater incorporation than chylomicrons prepared from the other fatty acids. This apparent selectivity may have been partly due to lower oxidation of 22:6(n-3) in the brain compared to the other fatty acids tested, based on recovered water-soluble oxidation products. The bulk of the radioactivity in the brain was found in phospholipid and triacylglycerol, except that animals injected with [1-14C]22:6(n-3) chylomicrons showed considerable incorporation also into the fatty acid fraction instead of triacylglycerol. These data show that chylomicrons may be an important source of fatty acids for the developing rat brain.
发育中的大脑从循环系统中获取多不饱和脂肪酸，但其机制和输送途径尚不确定。通过向成年供体大鼠十二指肠注入[1-¹⁴C]16:0、[1-¹⁴C]18:2(n-6)、[1-¹⁴C]18:3(n-3)或[1-¹⁴C]22:6(n-3)制备¹⁴C标记的乳糜微粒，并将其分别注入肝切除的2周龄乳鼠体内。在对大脑中滞留的血液进行轻微校正后，30分钟后乳糜微粒脂肪酸的掺入量几乎是共同注入的游离脂肪酸参考物的一半。与由其他脂肪酸制备的乳糜微粒相比，[1-¹⁴C]22:6(n-3)标记的乳糜微粒的掺入量平均高出65%。基于回收的水溶性氧化产物，这种明显的选择性可能部分是由于与其他测试脂肪酸相比，大脑中22:6(n-3)的氧化程度较低。除了注射[1-¹⁴C]22:6(n-3)乳糜微粒的动物外，大脑中的大部分放射性存在于磷脂和三酰甘油中，这些动物的脂肪酸部分而非三酰甘油中也有相当多的掺入。这些数据表明，乳糜微粒可能是发育中大鼠大脑脂肪酸的重要来源。
