Phorbol diester synergistically stimulates agonist-induced lipoxygenase product formation in murine macrophages

Murine peritoneal macrophages were preincubated with 12-O-tetradecanoylphorbol-13-acetate (100 ng/ml) and then exposed to various concentrations of calcium ionophore A23187. This combined treatment resulted in an elevated release of arachidonic acid metabolites that was synergistic in nature. Resolution of the [3H]products released into the medium revealed that the effect on the cyclooxygenase products 6-keto PGF1 and PGE2 were additive to less than additive (A23187 concentration dependent), the production of lipoxygenase products was synergistically enhanced, and the largest effect was on 12-HETE production.