Conversion of arachidonic acid to cyclooxygenase and lypoxygenase products, and incorporation into phospholipids in the mouse neuroblastoma clone, Neuro-2A

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Abstract
Arachidonic acid (AA) incorporation into phospholipids and cyclooxygenase and lipoxygenase mediated metabolism of arachidonic acid were studied in homogenized and intact Neuro-2A cells. When3H8-AA was added to homogenized cells and incubated 20 minutes, 39% of the label was converted to prostaglandins (PGs), 10% to hydroxy-eicosatetraenoic acid (HETE) and 26% was incorporated into phospholipids. PGE2 and PGF2α were the major PGs produced. Synthesis of PGs was blocked by 10 μM indomethacin and synthesis of PGs and HETE was blocked by 10 μM eicosatetraynoic acid (ETYA). The cell homogenate produced the 13, 14-dihydro-15-keto metabolites of PGE2 and PGF2α from3H8-AA and also converted exogenous3H7-PGE2 and3H8-PGF2α to metabolites. When intact cells were labeled for 24 hours with14C1-AA and the cells and media then analyzed, 75% of the radioactivity was incorporated into cellular phospholipids, 0.8% was converted to PGs and metabolites and 0.7% converted to HETE. Cells prelabeled for 24 hours were washed and incubated for 30 minutes in fatty acid free media. There was a 23% release of AA from phospholipids. One-fifth of the released AA was converted to HETE. PG synthesis in the intact resting cells was low. In summary, the Neuro-2A cell provides a good model system for studying arachidonic acid metabolism and incorporation into phospholipids in cells of neuronal origin.