Indomethacin inhibits arachidonic acid metabolism via lipoxygenase and cyclo-oxygenase in hamster isolated lungs

¹⁴C-Arachidonic acid (AA, 66 nmol) was injected into the pulmonary circulation of isolated perfused hamster lungs. The metabolites were analysed from the nonrecirculating perfusion effluent, which was extracted with ethyl acetate first at pH 7.4 (to extract unmetabolized AA, metabolites of lipoxygenase and HHT) and then at pH 3.5 for prostaglandins and thromboxanes. When indomethacin was infused into the pulmonary circulation, the metabolism of AA was decreased dose dependently. The amounts of all metabolites were decreased rather similarly by indomethacin. The present study indicates that indomethacin inhibits arachidonate metabolism via cyclo-oxygenase and lipoxygenase in hamster isolated lungs.