MODULATORY EFFECT OF 8-ISO-PGE(2) ON PLATELETS

1. 8-Iso-PGE(2) induced either reversible or irreversible aggregation of platelets in human platelet-rich plasma (PRP) or in the suspension of washed platelets (WP), The values of EC(50) for irreversible aggreg ation in PRP and WP were 4- and 2 mu M, respectively. 2. In rabbit PRP , 8-iso PGE(2) (0.1-100 mu M) itself did not induce or induced only re versible aggregation. 3. 8-Iso PGE(2) (0.1-20 mu M) potentiated adenos ine diphosphate-(ADP) induced platelet aggregation in both human and r abbit. The same effect also was found for adrenaline-induced platelet aggregation in rabbit. 4. The lower concentrations (0.2-0.5 mu M) of 8 -iso-PGE(2) decreased, and higher concentrations (1-2 mu M) increased platelet aggregating factor (PAF) induced aggregation in human PRP. In rabbit PRP, 8-iso-PGE(2) (0.02-200 mu M) had only a decreasing effect on PAF-induced aggregation. 5. The results suggest that low concentra tions of 8 iso PGE(2) can amplify or weaken platelet aggregation induc ed by various aggregatory agents. Copyright (C) 1997 Elsevier Science Inc.