Ionophore A23187 raises cyclic AMP levels in macrophages by stimulating prostaglandin E formation.

Abstract The calcium ionophore A23187 rapidly increased cAMP in rat peritoneal macrophages. The cAMP accumulation required extracellular Ca 2+ and could be inhibited by indomethacin. Determinations of prostaglandins in the incubation medium revealed that the ionophore A23187 induced a rapid release of prostaglandin E (PGE) and prostaglandin F (PGF). Synthesis of PGE and PGF occurred only in the presence of extracellular Ca 2+ but was not found to depend on a translocation of Ca 2+ into the cells. The data suggest a direct perturbation of the cell membrane by the ionophore A23187, leading to a release of prostaglandins which mediate an increase of cAMP.