The effects of vanadate and epidermal growth factor on the specific activities of phospholipase A2 and phosphatidylinositol-specific phospholipase C in human amnion cells.
We have evaluated the specific activity of phospholipase A2 (PLA2) and phosphatidylinositol-specific phospholipase C (PLC) in human amnion cells in monolayer culture that had not (CTL) or that had been treated with vanadate (VAN) and/or mouse epidermal growth factor (mEGF) for 4 h. It is known that both agents stimulate prostaglandin (PG) E2 synthesis in these cells. Phospholipase enzyme activities were determined in the 750 x g supernatant fraction of amnion cell homogenates under optimal in vitro conditions. The specific activity of PLA2 ranged from 1.1 to 1.25 nmol/mg protein/0.5 h and that of phosphatidylinositol-specific PLC from 1.04 to 1.2 mumol/mg protein/h. Treatment of amnion cell cultures with VAN and/or mEGF had no statistically significant effect on the specific activities of either phospholipases. Thus, we conclude that the stimulation of PGE2 production by VAN and mEGF is not due to an increase in the release of arachidonic acid from glycerophospholipid storage forms in human amnion cells.
Korte
K
K
Department of Obstetrics and Gynecology, University of Tuebingen, FRG.
Casey
M L
ML
D000650:Amnion / Q000201:enzymology*; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002478:Cells, Cultured; D015232:Dinoprostone / Q000096:biosynthesis; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005260:Female; D006801:Humans; D051379:Mice; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D011247:Pregnancy; D014638:Vanadates / Q000494:pharmacology*
D016718:Arachidonic Acid; D014638:Vanadates; D004815:Epidermal Growth Factor; D010741:Phospholipases A; D054467:Phospholipases A2; D010727:Phosphoric Diester Hydrolases; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D015232:Dinoprostone; D002118:Calcium