Captopril-induced enhancement of fMet-Leu-Phe-activated enzyme secretion from neutrophils.

Captopril enhanced exocytotic enzyme secretion from rabbit peritoneal neutrophils activated by suboptimal concentrations of fMet-Leu-Phe. For optimal enhancement the presence of Ca2+ was required. Captopril did not induce enzyme secretion by its own, and there was little effect on PMA-induced exocytosis. Cyclic GMP level of neutrophils was transiently enhanced by captopril. Methylene blue inhibited both captopril-induced enhancement of enzyme release and of cGMP levels. From our studies and from reports in the literature it appears that cGMP level-enhancing compounds may have both activating or inhibitory properties.