Inhibition of the n-formylmethionyl-leucyl-phenylalanine induced respiratory burst in human neutrophils by adrenergic agonists and prostaglandins of the E series.

Exogenous prostaglandins E1 and E2 and L-isoproterenol potently inhibited the production of superoxide anions by human neutrophils activated in vitro by n-formylmethionyl-leucyl-phenylalanine (FMLP). An estimated ID50 of 50 nM was found for all three agents while L-epinephrine and prostaglandin F2 alpha were 10 and 100 fold, respectively, less active. Inhibition occurred whether these agents were added before, together with, or after the addition of the tripeptide to cell suspensions. Cells treated with dibutyryl adenosine 3',5'-monophosphate also expressed reduced rates of superoxide synthesis thus suggesting that the hormonal inhibitors acted indirectly by stimulating membrane bound adenylate cyclase.