6-Keto-prostaglandin E1 inhibits the aggregation of human platelets

6-Keto-prostaglandin E1 (6-keto-PGE1) was found to have a similar potency to prostacyclin (PGI2) as an inhibitor of platelet aggregation. It caused a time and concentration dependent inhibition of ADP, collagen and epinephrine induced platelet aggregation, the dose ratios for 70% inhibition by 6-keto-PGE1, PGI2 and PGE1 being approximately 1 : 1 : 13. In doses similar to those of PGI2, 6-keto-PGE1 partially inhibited the release of [3H]-serotonin from platelet-rich plasma induced by collagen.