Prostaglandin synthesis by rheumatoid synovium and its stimulation by colchicine

The synthesis of prostaglandins by rheumatoid synovial tissue in organ culture was studied utilizing radioimmunoassay, with antisera to PGB₁, PGF_1α and PGF_2α. It was established that PGE₂ and PGF_2α were the major prostaglandins formed by analyses of culture media with the two antisera to PGF, before and after alkali treatment. Indomethacin at 5 μg/ml suppressed prostaglandin synthesis, usually to <1% of control cultures. Colchicine, 0.1 μg/ml resulted in marked stimulation of prostaglandin synthesis, in some cases over 10 fold. It is suggested, because of the colchicine effect, that the state of the microtubules may regulate the rate of prostaglandin biosynthesis. It is possible that prostaglandin E₂ produced by rheumatoid synovia may contribute to the pathogenesis of the inflammatory reaction and lead to destruction of juxta-articular bone in rheumatoid arthritis.