Stimuli which provoke secretion of azurophil enzymes from human neutrophils induce increments in adenosine cyclic 3'-5'-monophosphate.

1. Stimuli for human neutrophils were divided into two classes on the basis of their ability to induce degranulation: complete secretagogues provoked release of both azurophil and specific granules, while incomplete secretagogues only induced release of specific granules. 2. Complete secretagogues, which possessed the ability to induce secretion of azurophil granules, also induced transient increments in total cellular cyclic AMP levels: incomplete secretagogues did not. 3. Complete secretagogues, unlike the incomplete variety, also induced further increments of cyclic AMP in prostaglandin E1-pretreated neutrophils. 4. Inhibition of lysosomal enzyme release by prostaglandin E1 was closely correlated with elevated levels of cyclic AMP induced by the prostaglandin alone, than with the much higher transient increment in cyclic AMP produced by stimulation of prostaglandin E1-treated cells. 5. Our results describe the first biochemical difference between neutrophil responses associated with secretion of azurophil granules, as opposed to specific granules: transient increments in cyclic AMP.