Fujimoto Y, Shimada S, Fujikawa T, Sakuma S, Fujita T
Department of Hygienic Chemistry, Osaka University of Pharmaceutical Sciences, Japan.
Prostaglandins Leukot Essent Fatty Acids. 1991 Apr;42(4):251-6. doi: 10.1016/0952-3278(91)90091-i.
The effect of triarachidonin on the synthesis of prostaglandins in rabbit kidney medulla microsomes was examined. Medulla microsomes were incubated with triarachidonin in 0.1 M--Tris/HCl buffer (pH 7.0) containing reduced glutathione and hydroquinone and the formed prostaglandin E2, prostaglandin F2 alpha and prostaglandin D2 were measured by high-pressure liquid chromatography using 9-anthryldiazomethane for derivatization. The addition of triarachidonin (1-10 microM) stimulated prostaglandin formation in a dose-dependent manner. Under our incubation conditions rabbit kidney medulla was found to produce prostaglandin E2 mainly. When arachidonic acid, instead of triarachidonin, was added to the incubation mixture of microsomes, the identical profile of prostaglandin products was obtained. When the pH of the reaction mixture was changed from 7.0 to 8.0, the rate of triarachidonin-induced prostaglandin E2 formation was approximately 60% of that observed at pH 7.0. Studies utilizing Ca2+ and EGTA revealed that triacylglycerol lipase of kidney medulla is independent of Ca2+. The addition of epinephrine made the stimulatory effect of triarachidonin on prostaglandin E2 formation more pronounced. These results suggest that epinephrine-activated triacylglycerol lipase is present in the renomedullary microsomes, and this enzyme activity is a potential mediator of release of arachidonic acid for prostaglandin synthesis in the kidney medulla.
研究了三花生四烯酸对兔肾髓质微粒体中前列腺素合成的影响。将髓质微粒体与三花生四烯酸在含有还原型谷胱甘肽和对苯二酚的0.1M Tris/HCl缓冲液（pH 7.0）中孵育，使用9-蒽重氮甲烷进行衍生化，通过高压液相色谱法测定生成的前列腺素E2、前列腺素F2α和前列腺素D2。添加三花生四烯酸（1 - 10 microM）以剂量依赖的方式刺激前列腺素的形成。在我们的孵育条件下，发现兔肾髓质主要产生前列腺素E2。当向微粒体孵育混合物中添加花生四烯酸而非三花生四烯酸时，获得了相同的前列腺素产物谱。当反应混合物的pH从7.0变为8.0时，三花生四烯酸诱导的前列腺素E2形成速率约为pH 7.0时观察到的速率的60%。利用Ca2+和EGTA的研究表明，肾髓质的三酰甘油脂肪酶与Ca2+无关。肾上腺素的添加使三花生四烯酸对前列腺素E2形成的刺激作用更加明显。这些结果表明，肾上腺素激活的三酰甘油脂肪酶存在于肾髓质微粒体中，并且这种酶活性是肾髓质中用于前列腺素合成的花生四烯酸释放的潜在介质。
