Grewe M, Duyster J, Dieter P, Henninger H, Schulze-Specking A, Decker K
Biochemisches Institut Universität Freiburg, Germany.
Biol Chem Hoppe Seyler. 1992 Aug;373(8):655-64. doi: 10.1515/bchm3.1992.373.2.655.
Prostaglandin-synthesizing activities were demonstrated in cell-free extracts of rat Kupffer cells and characterized. The enzymatic properties of PGH2 synthase were found to be similar to those of synthases present in other organs or cell types. The specific activity of the enzyme was not changed by substances that stimulate prostanoid release by intact Kupffer cells; however, it was reduced by pretreatment of the cells with glucocorticoid hormones. On the other hand, the activities of PGD2 and PGE2 synthase were influenced differently by the kind of cell stimulation. While pretreatment of the intact cells with endotoxin and/or inhibition of protein kinase C led to an enhanced PGE2 formation in cell-free extracts, exposure to agents that enhance protein kinase C-dependent signalling pathways, e.g. phagocytotic stimuli or phorbol ester, suppressed PGE2 synthase activity and, therefore, led to enhanced PGD2 synthesis. It is in line with this observation that in vitro activation of protein kinase C of Kupffer cells resulted in a reduced PGE2 and an enhanced PGD2 synthase activity.
在大鼠枯否细胞的无细胞提取物中证实了前列腺素合成活性并进行了表征。发现PGH2合酶的酶学性质与其他器官或细胞类型中存在的合酶相似。该酶的比活性不受刺激完整枯否细胞释放前列腺素的物质影响；然而，用糖皮质激素预处理细胞会使其降低。另一方面，PGD2和PGE2合酶的活性受细胞刺激类型的影响不同。用内毒素预处理完整细胞和/或抑制蛋白激酶C会导致无细胞提取物中PGE2生成增加，而暴露于增强蛋白激酶C依赖性信号通路的试剂，如吞噬刺激物或佛波酯，则会抑制PGE2合酶活性，从而导致PGD2合成增加。与这一观察结果一致的是，体外激活枯否细胞的蛋白激酶C会导致PGE2减少和PGD2合酶活性增强。
