Differential metabolism of intracellular and extracellular arachidonic acid by decidual stromal cells and macrophages.

Term decidual stromal cells metabolized extracellular arachidonic acid to cyclo-oxygenase, lipoxygenase and epoxygenase products. Prostaglandins were the major metabolites from extracellular arachidonic acid. In contrast, intracellular arachidonic acid was metabolized mainly to an epoxygenase product, together with some lipoxygenase products. Decidual macrophages showed similar results, though these cells had higher production rates per cell of most metabolites. The calcium ionophore A23187 increased the levels of arachidonic acid released from the intracellular stores of decidual stromal cells and had variable effects on the production of cyclo-oxygenase, lipoxygenase and epoxygenase metabolites. Less than 15% of the total metabolites released from A23187-stimulated cells were cyclo-oxygenase products, which suggested that the cyclo-oxygenase products released by decidual stromal cells or macrophages may be mainly derived from extracellular arachidonic acid. This implies that the regulation of decidual cyclo-oxygenase may have a major role in determining prostaglandin output from this tissue.