Arachidonate Metabolism is Changed by Dipyridamole in Guinea Pig Isolated Lungs

Abstract: Fifty nmol of ¹⁴C-arachidonic acid was injected into the pulmonary circulation of guinea pig isolated lungs and the metabolites were analysed from the non-recirculating perfusion effluent. The main metabolites in the effluent were thromboxane B₂ (TxB₂), 6-keto-PGF_1α, a metabolite group migrating on TLC plate near to 15-keto-PGE₂ and a group of two metabolites (probably 12L-hydroperoxy- and 12L-hydroxy-5,8,10,14-eicosatetraenoic acids). Pulmonary infusion of dipyridamole (20 μM) increased the amount of TxB₂ in the perfusion effluent. The amounts of other metabolites were unchanged. 2, 20 or 100 μM of dipyridamole had no effect in vitro on the activity of NAD⁺-dependent 15-hydroxyprostaglandin dehydrogenase in the 100,000Xg supernatant fraction of guinea pig lungs.