Reactive oxygen species are involved in the activation of cellular phospholipase A2

Vanadate (V) potentiated (4- to 10-fold) the activation of cellular phospholipase A2 (PLA2) induced by H2O2 (H), a phorbol ester (T), a Ca(2+)-ionophore (A) and opsonized zymosan in macrophages. V+H induced in intact cells the activation and translocation of PLA2 and protein kinase C (PKC) to the plasma membrane. V+H and V+T+A induced strong chemiluminescence (CL) which was abrogated by a specific NADPH oxidase inhibitor diphenylene iodonium (DPI). DPI markedly suppressed the stimulation of PLA2 by V+T+A and V+OZ. The results suggest that the formation of endogenous reactive oxygen species (ROS) is important for PLA2 activation.