The metabolism of arachidonic acid in isolated perfused fetal and neonatal rabbit lungs

Abstract The developmental pattern of fetal and neonatal rabbit lungs to metabolize arachidonic acid (AA) to different cyclo-oxygenase products was studied in isolated rabbit lungs, which were perfused with Krebs bicarbonate buffer. 14 C-AA (66 nmol) was injected into the pulmonary circulation and the nonrecirculating perfusion effluent was collected for four minutes. About ten per cent of the injected radioactivity was found in the 0–4 min perfusion effluent. The metabolites of AA in the effluent were analyzed by thin layer chromatography. The major metabolites of AA were PGE 2 and its 15-keto-derivates, but also PGF 2α and its 15-keto-derivates, TXB 2 and 6-keto-PGF 1α were found in the effluent. The most drastic developmental change was the increase in the amount of 15-keto-metabolites of PGE 2 from late fetal period to the lungs of one day old rabbits (1.8 fold increase between birth and first postnatal day). Smaller changes were detected in the amounts of other cyclo-oxygenase products.