Arachidonic acid metabolism in cultured aortic endothelial cells. Effect of cAMP and 3-isobutyl-1-methylxanthine.
Arachidonic acid metabolism in cultured aortic endothelial cells. Effect of cAMP and 3-isobutyl-1-methylxanthine.
复制标题
培养的主动脉内皮细胞中的花生四烯酸代谢。
DOI：
10.1016/0006-2952(85)90109-1
复制
发表时间：
1985
影响因子：
5.8
通讯作者：
Kent,RS
中科院分区：
文献类型：
--
作者：
Whorton,AR;Collawn,JB;Montgomery,ME;Young,SL;Kent,RS
为了研究环磷酸腺苷（cAMP）调节血管组织中花生四烯酸代谢的假说，我们研究了腺苷酸环化酶激活剂佛司可林（FSK）和磷酸二酯酶抑制剂3-异丁基-1-甲基黄嘌呤（IBMX）对培养的猪主动脉内皮细胞合成前列环素（PGI 2）的影响。在这些实验中，缓激肽（1 μg/ml）和A23187（0.2 μM）有效刺激PGI 2生物合成（分别为9倍和10倍）。然而，前列腺素的合成反应，这些代理人不受FSK即使FSK升高细胞内cAMP水平的10倍。当与未刺激的细胞孵育时，IBMX未能升高基础cAMP水平。然而，用缓激肽刺激IBMX处理过的细胞（0.1而不是1.0或4.0 mM）确实导致cAMP水平升高，这可能是由于PGI 2的形成和随后的腺苷酸环化酶的激活。除了磷酸二酯酶抑制作用外，IBMX还以剂量依赖性方式抑制PGI 2的形成（1 mM时为72%），因此，在较高剂量的IBMX下，cAMP水平恢复到基线水平。因此，IBMX对前列环素合成的抑制不能归因于cAMP升高。在其他实验中，发现IBMX（1 mM）可直接抑制内皮细胞中花生四烯酸的释放（32%）和花生四烯酸的代谢（65%），并抑制花生四烯酸通过绵羊精囊微粒体转化为PGE 2（65%）。这些数据表明，IBMX直接抑制磷脂酶和环氧合酶活性。这些实验不支持cAMP调节培养的主动脉内皮细胞中这些酶的论点。
To investigate the hypothesis that cyclic AMP (cAMP) regulates arachidonic acid metabolism in vascular tissue, we have studied the effects of forskolin (FSK), an activator of adenylate cyclase, and 3-isobutyl-1-methylxanthine (IBMX), a phosphodiesterase inhibitor, on hormone-stimulated prostacyclin (PGI2) synthesis in porcine aortic endothelial cells grown in culture. In these experiments, bradykinin (1 μg/ml) and A23187 (0.2 μM) potently stimulated PGI2biosynthesis (9- and 10-fold respectively). However, prostaglandin synthesis in response to either of these agents was not affected by FSK even though FSK elevated intracellular levels of cAMP 10-fold. IBMX failed to elevate basal cAMP levels when incubated with unstimulated cells. Stimulation of IBMX-treated (0.1 but not 1.0 or 4.0 mM) cells with bradykinin, however, did result in increased cAMP levels, presumably due to PGI2formation and subsequent activation of adenylate cyclase. In addition to phosphodiesterase inhibition, IBMX inhibited PGI2formation (72% at 1 mM) in a dose-dependent manner so that, at higher doses of IBMX, cAMP levels returned to baseline. Thus, prostacyclin synthesis inhibition by IBMX could not be attributed to elevated cAMP. In other experiments, IBMX (1 mM) was found to directly inhibit arachidonic acid release (32%) and arachidonic acid metabolism (65%) in endothelial cells and to inhibit arachidonic acid conversion to PGE2by sheep seminal vesicle microsomes (65%). These data suggest that IBMX directly inhibits both phospholipase and cyclooxygenase activities. These experiments do not support the contention that cAMP regulates these enzymes in cultured aortic endothelial cells.