Macrophages from adjuvent arthritic rats preferentially synthetize prostacyclin.

Peritoneal macrophages obtained from rats 21 days after induction of adjuvant arthritis and maintained in culture for 20 h in presence of [14C]-arachidonic acid and 10% foetal calf serum were found to have increased capacity for synthetizing prostacyclin and diminished capacity for synthetizing PGE2 compared with macrophages from normal rats. Similar results were obtained when foetal calf serum was replaced by either normal or arthritic rat serum. Orally administered indomethacin inhibited the increased synthesis of prostacyclin.