Modulation of human neutrophil superoxide production by selective thromboxane synthetase inhibitor U63,557A.

Prostaglandin I2 and prostaglandins of E series have been known to inhibit human neutrophil superoxide production. To examine the effects of selective thromboxane synthetase inhibition on human neutrophil superoxide production (with or without platelets), neutrophils were incubated with U63,557A and stimulated with f-MLP, serum-activated zymosan or calcium ionophore A23187. U63,557A had no significant direct inhibitory effect on neutrophil superoxide production. On the other hand, in the presence of platelets in neutrophil suspension, U63,557A significantly reduced neutrophil superoxide production and increased prostaglandin I2 release. These data suggest that selective thromboxane synthetase inhibition may reduce neutrophil superoxide generation, most likely via increase in prostaglandin I2.