Indomethacin alters phospholipid and arachidonate metabolism in Tetrahymena pyriformis

Indomethacin an inhibitor of the cyclooxygenase pathway for arachidonate metabolism in vertebrates, totally inhibited 32P incorporation into phospholipids at a dose of 2.0 or 5.0 mM in Tetrahymena. Treatment with 0.1 mM indomethacin caused higher arachidonic acid (AA) incorporation into phosphatidylinositol (PI) and lower incorporation into phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (4,5) bisphosphate (PIP2). The same treatments in the presence of 3H-AA resulted in a significantly elevated 3H-diacylglycerol (DAG) level and free AA level compared with control cells. Indomethacin influences the lipid cycle and therefore the inositol phosphate cycle in Tetrahymena.