Arachidonic acid metabolism in isolated glomeruli from pig kidney was investigated. Arachidonic acid metabolism via cyclooxygenase was studied by three different methodological approaches: radioimmunoassay (RIA), high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). By all these techniques, the major prostaglandins (PG) formed by pig glomeruli appeared to be 6-keto-PGF1 alpha and PGF2 alpha, the former being the most abundant. RIA and GC-MS also detected lower amounts of thromboxane B2 (TxB2) and PGE2. This emphasises the similarity with human glomeruli, in which the main cyclooxygenase product has indeed been reported to be 6-keto-PGF1 alpha. The lipoxygenase activity in isolated pig glomeruli, as studied by HPLC, generated 15-HETE, 12-HETE and 5-HETE. These data demonstrate that isolated glomeruli from pig kidney possess cyclooxygenase as well as lipoxygenase activity. Since a marked functional similarity exists between human and pig kidney, the pig can be regarded as a good model for studying the influence of arachidonic acid metabolites on glomerular pathophysiology.