Table of Contents
Metal-Based Drugs
Volume 2, Issue 2, Pages 91-98

Stimulation of Phospholipase A2 by Toxic Main Group Heavy Metals: Partly Dependent on G-proteins?

Kernforschungszentrum Karlsruhe, Institute of Toxicology, P.O. Box 3640, Karlsruhe D-76021, Germany

Received 3 November 1994; Accepted 16 November 1994

Copyright © 1995 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Organometals induce platelet aggregation and inorganic metal ions such as Cd2+ or Pb2+ sensitise human blood platelets to aggregating agents and this action is associated with the liberation of arachidonic acid and eicosanoid formation. The same mechanism is observed using human leukaemia cells (HL-60) when treated with MeHgCl or Et3PbCl . The fatty acid liberation within human platelets and HL-60 cells could only be inhibited with phospholipase A2 inhibitors of different specificity.

Preincubation of the cells with pertussis toxin reduces the activation induced by Et3PbCl to a great extent. The non-catalytic B subunit, that only mediates the binding of the toxin to the cell membranes, has no effect at all. When summarised, these results suggest that one possible mechanism for the stimulation of phospholipase A2 by Et3PbCl functions via a G-protein dependent pathway.