Abstract
Prostaglandins E(2) and F(2alpha) were formed in response to ADP, L-epinephrine, or collagen by human platelets suspended in plasma containing citrate anticoagulant and stirred at 37 degrees C. The prostaglandins formed by platelets in response to collagen were rapidly released and the amounts formed were proportional to the amount of collagen added. The formation of the prostaglandins was associated with the single wave of aggregation induced by collagen or the second wave of aggregation induced by epinephrine. The above findings are discussed with reference to published studies on the biochemical changes occurring during platelet aggregation. It is suggested that the formation and release of prostaglandins is associated with the secretion of endogenous ADP and 5-hydroxytryptamine.