EFFECTS OF NONANAL, TRANS-2-NONENAL AND 4-HYDROXY-2,3-TRANS-NONENAL ON CYCLOOXYGENASE AND 12-LIPOXYGENASE METABOLISM OF ARACHIDONIC-ACID INRABBIT PLATELETS

The effects of nonanal, trans-2-nonenal and 4-hydroxy-2,3-trans-nonena l on the formation of thromboxane B-2 (TXB(2)), 12-hydroxy-5,8,10-hept adecatrienoic acid (HHT) and 12-hydroxy-5,8,10,14-eicosatetraenoic aci d (12-HETE) from exogenous arachidonic acid in washed rabbit platelets were examined. Nonanal and trans-2-nonenal at concentrations ranging from 0.25 to 2 mu M inhibited TXB(2), HHT and 12-HETE formation, reduc ing the amounts of these three arachidonic acid metabolites by 50% at nonanal and trans-2-nonenal concentrations of approximately 0.25 mu M. The inhibition of TXB(2), HHT and 12-HETE formation induced by 4-hydr oxy-2,3-trans-nonenal (50% inhibition by 4-hydroxy-2,3-trans-nonenal a t a concentration of approximately 100 mu M) was 400 times weaker than that induced by nonanal and trans-2-nonenal. These results suggest th at nonanal and trans-2-nonenal can be modulators of platelet arachidon ic acid metabolism by affecting the activity of cyclooxygenase and 12- lipoxygenase.