Metabolism of phospholipids by polymorphonuclear leukocytes

Abstract

By incubating homogenates of polymorphonuclear leukocytes obtained from rabbit-peritoneal exudates with various 32P-labeled phosphoglycerides the following reactions were identified: Lecithin → Lysolecithin and fatty acid (1) Lysolecithin → Glycerylphosphorylcholine and fatty acid (2) Lysolecithin → Lecithin (3) The mechanism of the last reaction appears to be the recently postulated (Erbland and Marinetti) pathway:

2 lysolecithin → lecithin and glycerylphosphorylcholine. This conclusion is based upon: (a) [32P]lysolecithin accumulation occurred without appreciable incorporation of [14C]linoleic acid. (b) Lysolecithin carrying 32P in the phosphorylcholine moiety and 14C in the fatty acid yielded lecithin with a 14C/32P ratio 2 times that of the original lysolecithin. (c) ATP and CoA did not stimulate [32P] lecithin formation nor incorporation of [14C]linoleic acid.

Lysolecithin is a membrane-lytic agent. Its production and removal by conversion to glycerylphosphorylcholine and lecithin may therefore play a role in the lysis and renewal of cellular membranes.