Effects of platelet aggregation and adenosine 3':5'-monophosphate on the synthesis of thromboxane B2 in human platelets.

This study was undertaken to investigate the effect of cyclic AMP on the conversion of arachidonic acid to TXB2 (thromboxane B2). Results from the study showed that both platelet aggregation and the conversion of arachidonic acid to TSB2 in platelets were inhibited by PGI2-induced elevation of cyclic AMP levels in platelet rich plasma. Colchicine inhibited platelet aggregation and caused a similar inhibition of TXB2 formation but did not alter AMP concentrations. This suggests that inhibition of platelet aggregation prevents the synthesis of TXB2. The parallel dose-dependent inhibition of platelet aggregation and TXB2 formation obtained with both PGI1 and colchicine gives further evidence for this hypothesis.