INVOLVEMENT OF PROSTAGLANDIN ENDOPEROXIDE FORMATION IN ELEVATION OF CYCLIC-GMP LEVELS DURING PLATELET-AGGREGATION

Abstract

Arachidonic acid- or collagen-induced aggregation was accompanied by a progressive elevation in the level of cyclic[c]GMP in washed human platelets with no significant alteration in the concentration of cAMP. The extent of the increase in cGMP was proportional to the concentration of arachidonic acid added. Enhanced accumulation of cGMP produced by arachidonic or collagen was prevented by prior exposure of platelets to aspirin or indomethacin. Prostaglandin [PG] endoperoxide G2 caused platelet aggregation and an increase in cGMP concentration; neither event was blocked by PG synthesis inhibitors. The generation of PG endoperoxides is probably a step in the sequence of events in platelet aggregation leading to the enhanced accumulation of cGMP.