Changes in activity of cytosolic phospholipase A(2) in human amnion at parturition
Changes in activity of cytosolic phospholipase A(2) in human amnion at parturition
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DOI：
10.1016/s0002-9378(97)70459-9
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发表时间：
1997-07-01
影响因子：
9.8
通讯作者：
Myatt, L
中科院分区：
文献类型：
--
作者：
Skannal, DG;Brockman, DE;Myatt, L
目的：本研究的目的是确定是否增加胞浆磷脂酶A（2）活性介导的花生四烯酸动员，为前列腺素的合成在羊膜在partialization.Study设计：羊膜收集后立即交付从四组患者：早产（37周），没有劳动或劳动，并储存在-70 ℃。将组织匀浆并以100，000 g离心1小时，使用碳14标记的1-硬脂酰-2花生四烯酸磷脂酰胆碱加10 μ mol/L未标记底物和5 mmol/L钙的10 mmol/L N-2-羟乙基哌嗪-N-2-乙磺酸（pH 7.4）溶液测定胞浆磷脂酶A（2）活性。在30 ℃下，以一式两份+/- 10 μ mol/L花生四烯基三氟甲基酮（一种细胞溶质磷脂酶A（2）活性的特异性抑制剂）孵育45分钟。总胞浆磷脂酶A（2）活性（单位：皮摩尔花生四烯酸/分钟/毫克蛋白质）计算为在存在和不存在花生四烯基三氟甲基酮的情况下活性之间的差异为（平均值+/- SE）如下：早产未分娩（n = 7）8.94 +/- 3.08，早产伴分娩（n = 6）6.79 +/- 2.31，足月未分娩（n = 7）14.85 +/- 1.66，足月伴分娩（n = 5）5.51 +/- 1.52。酶活性随着胎龄的增加而增加，在足月无分娩组中最高。胞浆磷脂酶A（2）活性随产程的进行而显著降低（p < 0.05）。结论：羊膜中总细胞胞浆磷脂酶A（2）活性在临产前最高，但在临产过程中总活性被耗尽，导致胎盘娩出后测得的活性较低。底物特异性和羊膜总胞质磷脂酶A（2）活性随分娩的变化强烈提示在分娩时花生四烯酸动员和前列腺素合成的介导中起作用。
OBJECTIVE: The purpose of this study was to determine whether increased cytosolic phospholipase A(2) activity mediated arachidonic acid mobilization for prostaglandin synthesis in amnion at parturition.STUDY DESIGN: Amnion was collected immediately after delivery from four groups of patients: preterm (37 weeks) with no labor or labor and stored at -70 degrees C. Tissues were homogenized and centrifuged for 1 hour at 100,000g, and cytosol was assayed for cytosolic phospholipase A(2) activity with use of carbon 14-labeled 1-stearoyl-2 arachidonyl phosphatidylcholine plus 10 mu mol/L unlabeled substrate and 5 mmol/L calcium in 10 mmol/L N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid, pH 7.4. Incubations were performed in duplicate +/- 10 mu mol/L arachidonyl trifluoromethyl ketone, a specific inhibitor of cytosolic phospholipase A(2) activity, at 30 degrees C for 45 minutes.RESULTS: Total cytosolic phospholipase A(2) activity (in picomoles of arachidonic acid per minute per milligram of protein) calculated as the difference between the activity in the presence and absence of arachidonyl trifluoromethyl ketone was (mean +/- SE) as follows: preterm no labor (n = 7) 8.94 +/- 3.08, preterm with labor (n = 6) 6.79 +/- 2.31, term no labor (n = 7) 14.85 +/- 1.66, and term with labor (n = 5) 5.51 +/- 1.52. Enzyme activity increased with gestational age and was highest in the term no labor group. A significant decrease in cytosolic phospholipase A(2) activity occurred with labor (p < 0.05). The greatest decrease in activity was in the term group (p < 0.05).CONCLUSION: Total cellular cytosolic phospholipase A(2) activity in amnion is highest in anticipation of labor but during labor total activity is depleted, resulting in the low activity measured after delivery of the placenta. The substrate specificity and changes in amnion total cytosolic phospholipase A(2) activity with labor strongly suggests a role in mediation of arachidonic acid mobilization and prostaglandin synthesis at labor.