Release of type II phospholipase a, immunoreactivity and phospholipase A2 enzymatic activity from human placenta

Farrugia, W., Rice, G. E., Wong, M. H., Scott, K. F. and Brennecke, S. P. (1997) Release of type II phospholipase a, immunoreactivity and phospholipase A2 enzymatic activity from human placenta. Journal of Endocrinology, 153 1: 151-157. doi:10.1677/joe.0.1530151


Author Farrugia, W.
Rice, G. E.
Wong, M. H.
Scott, K. F.
Brennecke, S. P.
Title Release of type II phospholipase a, immunoreactivity and phospholipase A2 enzymatic activity from human placenta
Journal name Journal of Endocrinology   Check publisher's open access policy
ISSN 0022-0795
1479-6805
Publication date 1997-04
Sub-type Article (original research)
DOI 10.1677/joe.0.1530151
Volume 153
Issue 1
Start page 151
End page 157
Total pages 7
Place of publication Bristol, United Kingdom
Publisher BioScientifica
Language eng
Formatted abstract
The aim of this study was to determine whether Type II phospholipase A2 (PLA2) is released from late pregnant human placental tissue. placental explants were incubated in vitro and the release of immunoreactive (ir) Type II PLA2 and PLA2 enzymatic activity into the medium was determined. Both irType II PLA2 and PLA2 enzymatic activity accumulated in the incubation medium in a time-dependent manner (P < 0.0001). This release was not associated with a loss of cell membrane integrity, as indicated by measurement of the intracellular enzyme, lactate dehydrogenase, in the incubation medium. The concentration of irType II PLA2 and PLA2 enzyme activity present in incubation medium were significantly correlated (P < 0.01). Consistent with the hypothesis that Type II PLA2 may be stored in secretory granules within human placental tissue, incubation in the presence of a membrane depolarising concentration of KCl (60 mM) caused the release of irType II PLA2 2.0-fold (P < 0.001). PLA2 enzyme activity released into the incubation medium displays biochemical characteristics consistent with those previously reported for secretory PLA2 isozymes, that is, a requirement for micromolar concentrations of calcium for optimal enzyme activity, inhibited by reducing agents, such as dithiothreitol and insensitive to heat inactivation. The data obtained in this study establish that irType II PLA2 is released from term placenta, when incubated in vitro. The release of this extracellarly-active PLA2 isozyme may contribute to gestational and labour-associated increases in glycerophospholipid metabolism and prostaglandin formation.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: UQ Centre for Clinical Research Publications
 
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