Chemoattractants stimulate degradation of methylated phospholipids and release of arachidonic acid in rabbit leukocytes.

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Abstract
When rabbit peritoneal leukocytes were treated with chemoattractants such as fMet-Leu-Phe, an apparent decrease of [3H]methyl incorporation into the lipid fraction from L-[methyl-3H]methionine was observed. This decrease was a result of increased degradation of methylated phospholipids, not of decreased synthesis. Chemotactic peptides did not affect the metabolism of the phospholipids in which [methyl-14C]choline was incorporated. The disappearance of the [3H]methyl group was associated with the release of [1-14C]arachidonic acid from phospholipids prelabeled with these compounds. The activation by chemoattractants of phospholipase A2, an enzyme that removes an unsaturated fatty acid from phospholipids was suggested. The order of potency of chemoattractants for the stimulated degradation of phospholipids was in good agreement with that for chemotaxis. Mepacrine (quinacrine) and hydrocortisone inhibited and a phorbol ester enhanced chemotaxis and phospholipase A2 activity. Close association of the metabolism of methylated phospholipids with chemotaxis in rabbit peritoneal leukocytes was suggested.