Release of phospholipase A2 activity from rabbit peritoneal neutrophils by f-Met-Leu-Phe

Rabbit peritoneal neutrophils secrete phospholipase A2 activity in response to f-Met-Leu-Phe (FMLP). The secretion of phospholipase A2, like that of the known granule enzymes, requires cytochalasin B and is enhanced by extracellular Ca2+, and the time course of the release is rapid, being completed in less than a minute. The concentration dependence of the secretion of the phospholipase is the same as that of the known granule enzymes up to 10(-9) M FMLP. At this concentration, the release of the known granule enzymes reaches a maximum, but that of phospholipase A2 does not until 10(-8) M FMLP. The amount of enzyme activity released plus the amount of enzyme activity remaining in the pellet is distinctly greater than the total enzyme activity extractable from the cell before release. The phospholipase secreted is active in the neutral to alkaline range, requires Ca2+, is inhibited by low levels of detergent, and is of A2 specificity.