Elsevier

Placenta

Volume 20, Issue 1, January 1999, Pages 21-26
Placenta

Regular Article
Secretory Type II PLA2Immunoreactivity and PLA2Enzymatic Activity in Human Gestational Tissues Before, During and After Spontaneous-onset Labour at Term

https://doi.org/10.1053/plac.1998.0341Get rights and content

Abstract

Arachidonic acid mobilization by phospholipase A2(PLA2) and subsequent prostaglandin synthesis is thought to be a pivotal event in the onset and/or maintenance of human labour. The purpose of this study was to quantify secretory PLA2(sPLA2) and non-secretory PLA2enzymatic activity and type II sPLA2immunoreactivity in human gestational tissues before, during and after labour of spontaneous onset. Placental tissue and fetal membranes were collected from women before, during and after spontaneous-onset labour at term and stored at −80°C. PLA2activity in supernatants was quantified by radiolabelled substrate assay (14C-phosphatidylethanolamine) with and without 12.5 mmdithiothreitol (DTT) to separate enzymatic activity contributed by secretory and non-secretory PLA2components. Immunoreactive type II PLA2in supernatants was determined by a monoclonal, non-competitive sandwich ELISA. Total PLA2enzymatic activity in amnion, choriodecidua and placenta was not significantly different before, during and after labour (n=18–20). Likewise, non-secretory enzymatic activity was not significantly different before (n=9), during (n=10) and after labour (n=9) in any of the three types of gestational tissue examined. Although immunoreactive type II PLA2was significantly higher in the placenta (P<0.01) compared to amnion and choriodecidua, there was no significant difference in immunoreactive type II PLA2within each tissue group according to labour status (n=18–20). Overall, no change in PLA2secretory or non-secretory enzymatic activity or immunoreactive type II PLA2could be detected throughout the peripartum period.

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f1

To whom correspondence should be addressed at: Perinatal Research Centre, Royal Women’s Hospital, 132 Grattan Street, Carlton, Victoria, Australia.

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