Germain A M, Smith J, Casey M L, MacDonald P C
Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas, Southwestern Medical Center, Dallas 75235-9051.
J Clin Endocrinol Metab. 1994 Feb;78(2):463-70. doi: 10.1210/jcem.78.2.8106636.
This investigation was conducted to evaluate the potential capacity of the human fetal membranes-decidua parietalis, and in particular the chorion laeve, to degrade uterotonins that are produced in amnion, are present in amniotic fluid, or both. The four uterotonins that have been evaluated most frequently as myometrial contractants potentially involved in the initiation of human parturition are prostaglandins, oxytocin, endothelin-1, and platelet-activating factor. We assessed the levels of mRNA and the specific activities (SAs) of enkephalinase (the plasma membrane endopeptidase that degrades endothelins) and prostaglandin dehydrogenase (PGDH) in human fetal membranes, i.e. amnion and chorion leave, and in decidua parietalis. The SA of oxytocinase (which inactivates oxytocin) in these tissues also was determined. The SA of enkephalinase in chorion laeve from all anatomical sites (singleton and diamnionic-dichorionic twin placentae) in all pregnancies studied (mean +/- SEM, 95 +/- 7.9 ng/min.mg protein; n = 28) is similar to that in human fetal kidney (89.5 +/- 2.8; n = 6). Kidney tissue is believed to be one of the richest sources of enkephalinase. The SAs of enkephalinase in amnion (18.3 +/- 2.3 nmol/min.mg protein; n = 29) and in decidua parietalis (31.8 +/- 6.7; n = 20) also were high, but significantly less than that in chorion leave. The level of enkephalinase mRNA in chorion laeve in singleton pregnancies is high, as is the SA of enkephalinase (111.9 +/- 10.6 nmol/min.mg protein; n = 17). In paired chorion laeve tissues from five diamnionic-dichorionic twin placentae, the SAs of enkephalinase in reflected chorion laeve (74 +/- 12.8; P < 0.06 compared with singletons) and fused chorion laeve (64.8 +/- 6.5; P < 0.001 compared with singletons) were similar. The SA of PGDH in reflected chorion leave (46.3 +/- 6.9 nmol/min.mg protein; n = 19) was significantly greater than that in decidua (16 +/- 5.5; n = 15). There was a significant correlation between the levels of PGDH mRNA and PGDH enzyme SA. In fused chorion laeve of diamnionic-dichorionic twin placentae, the SA of PGDH (14.9 +/- 7.3; n = 4) was much less than that in reflected chorion laeve of the same twin pregnancy (70.5 +/- 14.7; n = 4). PGDH mRNA was not detectable in amnion tissue (n = 5) by northern analysis, and the SA of PGDH (< 1.2 +/- 1.0; n = 6) in amnion was undetectable or near the lower limit of assay detection.(ABSTRACT TRUNCATED AT 400 WORDS)
本研究旨在评估人胎膜-子宫壁蜕膜，尤其是平滑绒毛膜降解在羊膜中产生、存在于羊水或两者皆有的子宫收缩素的潜在能力。作为可能参与人类分娩启动的子宫肌层收缩剂，最常被评估的四种子宫收缩素是前列腺素、催产素、内皮素-1和血小板活化因子。我们评估了人胎膜（即羊膜和平滑绒毛膜）以及子宫壁蜕膜中脑啡肽酶（降解内皮素的质膜内肽酶）和前列腺素脱氢酶（PGDH）的mRNA水平和比活性（SAs）。还测定了这些组织中催产素酶（使催产素失活）的比活性。在所有研究的妊娠中（均值±标准误，95±7.9 ng/min·mg蛋白；n = 28），来自所有解剖部位（单胎和双羊膜-双绒毛膜双胎胎盘）的平滑绒毛膜中脑啡肽酶的比活性与人胎儿肾脏中的比活性相似（89.5±2.8；n = 6）。肾脏组织被认为是脑啡肽酶最丰富的来源之一。羊膜（18.3±2.3 nmol/min·mg蛋白；n = 29）和子宫壁蜕膜（31.8±6.7；n = 20）中脑啡肽酶的比活性也较高，但显著低于平滑绒毛膜中的比活性。单胎妊娠中平滑绒毛膜中脑啡肽酶mRNA水平较高，脑啡肽酶的比活性也较高（111.9±10.6 nmol/min·mg蛋白；n = 17）。在来自五个双羊膜-双绒毛膜双胎胎盘成对的平滑绒毛膜组织中，反折侧平滑绒毛膜（74±12.8；与单胎相比P < 0.06）和融合侧平滑绒毛膜（64.8±6.5；与单胎相比P < 0.00）中脑啡肽酶的比活性相似。反折侧平滑绒毛膜中PGDH的比活性（46.3±6.9 nmol/min·mg蛋白；n = 19）显著高于蜕膜中的比活性（16±5.5；n = 15）。PGDH mRNA水平与PGDH酶比活性之间存在显著相关性。在双羊膜-双绒毛膜双胎胎盘的融合侧平滑绒毛膜中，PGDH的比活性（14.9±7.3；n = 4）远低于同一双胎妊娠反折侧平滑绒毛膜中的比活性（70.5±14.7；n = 4）。通过Northern分析在羊膜组织（n = 5）中未检测到PGDH mRNA，羊膜中PGDH的比活性（< 1.2±1.0；n = 6）未检测到或接近检测下限。（摘要截断于400字）
