METABOLISM OF ARACHIDONIC-ACID TO EPOXYEICOSATRIENOIC ACIDS, HYDROXYEICOSATETRAENOIC ACIDS, AND PROSTAGLANDINS IN CULTURED RAT HIPPOCAMPAL ASTROCYTES
METABOLISM OF ARACHIDONIC-ACID TO EPOXYEICOSATRIENOIC ACIDS, HYDROXYEICOSATETRAENOIC ACIDS, AND PROSTAGLANDINS IN CULTURED RAT HIPPOCAMPAL ASTROCYTES
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DOI：
10.1111/j.1471-4159.1993.tb03550.x
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发表时间：
1993-07-01
影响因子：
4.7
通讯作者：
ELLIS, EF
中科院分区：
文献类型：
--
作者：
AMRUTHESH, SC;BOERSCHEL, MF;ELLIS, EF
我们最近发现脑切片能够通过环氧酶途径代谢花生四烯酸。本研究的目的是开始确定单个脑细胞类型形成表氧化酶代谢物的能力。我们已经研究了星形胶质细胞环氧合酶途径，也证实了环氧合酶和脂氧合酶系统的代谢。培养的大鼠海马星形胶质细胞匀浆，当与放射性标记的[H-3]-花生四烯酸孵育时，形成的产物在四个主要的R17-30组中洗脱。R42-50、R51-82和R83-90基于其在反相HPLC中的保留时间。通过正相HPLC和第二反相HPLC系统将这些级分进一步分离成多达13个峰。通过气相色谱/电子轰击-质谱法对各峰中的主要组分进行结构表征。基于HPLC保留时间和气相色谱/电子碰撞-质谱分析，极性更强的级分（R17-30）含有前列腺素D2作为主要的环氧合酶产物。次要产物包括6-酮前列腺素F1 α、前列腺素E2、前列腺素F2 α和血栓素B2。组分R42-50、R51-82和R83-90含有环氧合酶和脂氧合酶样产物。组分R83-90中的主要代谢产物是5，6-环氧二十碳三烯酸（EET）。组分R51-82含有14，15-和8，9-雌二醇、12-和5-羟基二十碳四烯酸以及8，9-和5，6-二羟基二十碳三烯酸（DHE 3）。在R42-50级分中，14，15-DHET是主要产物。当放射性标记的[H-3] 14，15-EET与星形胶质细胞匀浆一起孵育时，其迅速代谢为[H-3] 14，15-DHET。代谢被抑制亚微摩尔浓度的4-苯基查尔酮氧化物，一种有效的环氧化物水解酶活性抑制剂。未观察到14，15-DHET形成其他极性代谢物，如三醇或环氧醇。总之，星形胶质细胞容易将花生四烯酸代谢为14，15-EET、5，6-EET及其邻二醇。以前的研究表明，这些产品可能会影响神经功能和脑血流。
We have recently shown that brain slices are capable of metabolizing arachidonic acid by the epoxygenase pathway. The purpose of this study was to begin to determine the ability of individual brain cell types to form epoxygenase metabolites. We have examined the astrocyte epoxygenase pathway and have also confirmed metabolism by the cyclooxygenase and lipoxygenase enzyme systems. Cultured rat hippocampal astrocyte homogenate, when incubated with radiolabeled [H-3]-arachidonic acid, formed products that eluted in four major groups designated as R17-30. R42-50, R51-82, and R83-90 based on their retention times in reverse-phase HPLC. These fractions were further segregated into as many as 13 peaks by normal-phase HPLC and a second reverse-phase HPLC system. The principal components in each peak were structurally characterized by gas chromatography/electron impact-mass spectrometry. Based on HPLC retention times and gas chromatography/electron impact-mass spectrometry analysis, the more polar fractions (R17-30) contained prostaglandin D2 as the major cyclooxygenase product. Minor products included 6-keto prostaglandin F1alpha, prostaglandin E2, prostaglandin F2alpha, and thromboxane B2. Fractions R42-50, R51-82, and R83-90 contained epoxygenase and lipoxygenase-like products. The major metabolite in fractions R83-90 was 5,6-epoxyeicosatrienoic acid (EET). Fractions R51-82 contained 14,15- and 8,9-EETs, 12- and 5-hydroxyeicosatetraenoic acids, and 8,9- and 5,6-dihydroxyeicosatrienoic acids (DHETs). In fractions R42-50, 14,15-DHET was the major product. When radiolabeled [H-3]l 4,15-EET was incubated with astrocyte homogenate, it was rapidly metabolized to [H-3] 1 4,15-DHET. The metabolism was inhibited by submicromolar concentration of 4-phenylchalcone oxide, a potent inhibitor of epoxide hydrolase activity. Formation of other polar metabolites such as triols or epoxyalcohols from 14,15-DHET was not observed. In conclusion, astrocytes readily metabolize arachidonic acid to 14,15-EET, 5,6-EET, and their vicinal-diols. Previous studies suggest these products may affect neuronal function and cerebral blood flow.