ACTIVATION OF PHOSPHOLIPASE-D IN CULTURED HUMAN AMNION CELLS

The regulation of phospholipase D (PLD) activity in the human amniotic membrane was examined using primary cultures of amnion cells. Culture d amnion cells were labelled with [H-3]oleic acid, and PLD activity wa s determined as the amount of [H-3]phosphatidylethanol (PEt) produced during incubation in the presence of 0.1% ethanol. PLD activity in cul tured amnion cells was activated by addition of arginine vasopressin a nd oxytocin. PLD activity was also stimulated by treatment with arachi donic acid, the product of phospholipase A(2) (PLA(2)), and phospholip ase C (PLC). These results indicate that PLD in amnion cells is activa ted by substances present in amniotic fluid, and that cross-talk betwe en phospholipases A(2), C and D may occur in amnion cells.