Effect of catecholamines on the bactericidal activity of polymorphonuclear leukocytes.

Epinephrine, norepinephrine, and dihydroxyphenylalanine at 8 mm concentrations prevented iodination of zymosan by intact neutrophils and decarboxylation of l-alanine by leukocyte sonic extracts. The same concentration of epinephrine also reduced bactericidal activity of the leukocyte against Staphylococcus aureus, Enterobacter cloacae, and Proteus rettgeri without decreasing phagocytosis of bacteria. Spectral studies indicated that epinephrine interferes with the myeloperoxidase-mediated reactions by competing for available H(2)O(2) via its enzymatic oxidation to adrenochrome. These findings support a mechanism in which H(2)O(2) plays an important role in the bactericidal activity of the leukocyte.