Polymorphonuclear leukocytes produce thromboxane A2-like activity during phagocytosis.

Homogenates of phagocytosing polymorphonuclear leukocytes obtained from rabbit peritoneum were incubated with the prostaglandin endoperoxides PGG2 or PGH2. After 2 min at 0degree C, incubation mixtures contained an increased rabbit aorta contracting activity. Ether extracts of incubation mixtures contained a substance which contracted the superfused strips of rabbit aorta and coeliac artery and had a half life which was similar to thromboxane A2. The generation of thromboxane A2-like activity from PG endoperoxides was prevented by boiling the homogenate prior to incubation, or by pretreatment with benzydamine, a drug which blocks thromboxane formation in platelets. Production of thromboxane A2-like material by leukocyte homogenates was compared with platelet microsomal thromboxane synthetase.