Single-blind study of epoprostenol and 6-keto-prostaglandin E1 in man: effects of platelet aggregation and plasma renin.

The effects of epoprostenol (PGI2, 2-8 ng kg-1 min-1) and 6-keto-prostaglandin E1 (6-keto-PGE1, 7.5-30 ng kg-1 min-1) on ADP-induced platelet aggregation, blood pressure (BP), heart rate and plasma renin activity (PRA) were studied in six healthy male volunteers. During graded intravenous administration of PGI2, platelet aggregation was inhibited at a minimum dose of 4 ng kg-1 min-1. The dose required to produce the same degree of platelet inhibition was approximately 15 ng kg-1 min-1 for 6-keto-PGE1. Diastolic BP was significantly reduced and PRA was increased by PGI2 at a dose greater than 8 ng kg-1 min-1. In contrast, 6-keto-PGE1 did not produce BP and PRA changes up to a dose of 30 ng kg-1 min-1. These data indicate that PGI2 has approximately four times more potent antiplatelet activity than 6-keto-PGE1 on a molar basis in man. The cardiovascular and PRA changes were less prominent for 6-keto-PGE1 than PGI2.