Influence on platelet activity and red cell fluidity of epoprostenol and two stable prostacyclin analogues in vitro.

Not only epoprostenol (prostacyclin, PGI2) but also the two stable prostacyclin analogues CG 4203 (oxacyclic) and CG 4305 (carbacyclic) cause concentration dependent inhibition of thrombocyte function: pseudopod formation and aggregation after stimulation with ADP, collagen and arachidonic acid are inhibited to an extent dependent on dose. ADP-induced aggregation is inhibited 45% by 10 nmol/l epoprostenol 47% by 50 nmol/l CG 4203 and 25% by 50 nmol/l CG 4305. Epoprostenol itself improves red cell fluidity to an extent dependent on concentration, but the two analogues tested show no such effect.