Azavache V, Cuevas C, Bosch V
Sección de Lipidología del Instituto de Medicina Experimental, Facultad de Medicina U.C.V. Caracas, Venezuela.
Arch Latinoam Nutr. 1998 Sep;48(3):216-20.
We address here the issue concerning the origin of essential long chain polyunsaturated fatty acids (LC-PUFA) needed for early postnatal brain development. Normal newborn rats 1, 5, 10 and 20 day-old were decapitated, immediately after, the livers were processed to obtain the microsomal fraction and its delta 6 fatty acid desaturase activity and fatty acid composition were determined. Samples of plasma, whole homogenized brain hemispheres and milk contained in the gastric cavity of the suckling rats, were analyzed to obtained their fatty acid composition. We fond that the rat neonate has a very low delta 6 desaturase activity in liver microsomes as compared with the adult. In contrast, there is a considerable quantity of DHA an AA in the milk, liver microsomes, plasma lipids and brain. In conclusion, we propose that brain DHA and AA cannot be derived substantially through liver synthesis, but through the availability of these preformed fatty acids in the milk. These fatty acids are concentrated in liver microsomes and then secreted into plasma lipid pool to reach finally to brain structures.
我们在此探讨出生后早期大脑发育所需的必需长链多不饱和脂肪酸（LC-PUFA）的来源问题。对1日龄、5日龄、10日龄和20日龄的正常新生大鼠进行断头处理，随后立即对肝脏进行处理以获得微粒体部分，并测定其δ6脂肪酸去饱和酶活性和脂肪酸组成。分析了血浆样本、全脑匀浆半球以及哺乳大鼠胃腔中的乳汁，以获得它们的脂肪酸组成。我们发现，与成年大鼠相比，新生大鼠肝脏微粒体中的δ6去饱和酶活性非常低。相反，乳汁、肝脏微粒体、血浆脂质和大脑中存在相当数量的DHA和AA。总之，我们认为大脑中的DHA和AA基本上不是通过肝脏合成而来，而是通过乳汁中这些预先形成的脂肪酸获得。这些脂肪酸在肝脏微粒体中浓缩，然后分泌到血浆脂质池中，最终到达脑结构。
