Phosphatidylcholine and phosphatidylethanolamine metabolites may regulate brain phospholipid catabolism via inhibition of lysophospholipase activity

Abstract

Brain levels of glycerophosphocholine (GPC) and glycerophosphoethanolamine (GPE), abundant metabolites of phosphatidylcholine and phosphatidylethanolamine, are increased in several disorders of the human brain. To determine whether accumulation of these compounds may alter phospholipid metabolism, we assessed the ability of GPE and GPC to modulate the activities of phospholipase A 2, lysophospholipase, and other enzymes involved in phospholipid metabolism, in preparations of human brain parietal cortex. GPC and GPE acted as competitive inhibitors of lysophospholipase activity, but failed to alter the activity of the other enzymes tested. Our results suggest that GPC and GPE may normally act to inhibit lysophospholipid hydrolysis, thereby reducing the rate of membrane phospholipid degradation.