Arachidonate metabolism is changed by dipyridamole in guinea pig isolated lungs

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-PGF1 alpha, 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 microM) increased the amount of TxB2 in the perfusion effluent. The amounts of other metabolites were unchanged, 2, 20 or 100 microM of dipyridamole had no effect in vitro on the activity of NAD+-dependent 15-hydroxyprostaglandin dehydrogenase in the 100,000 X g supernatant fraction of guinea pig lungs.