Turnover of phospholipid linoleic and arachidonic acids in human platelets from plasma lecithins.

Incubation of platelet-rich plasma with high density lipoproteins labeled either with 1-acyl-2[1-14c]-arachidonoyl-sn-glycero-3-phosphocholine or 1-acyl-2-[1-14c]linoleoyl-sn-glycero-3-phosphocholine showed the existence of a pool of phosphatidylcholine in platelets, which rapidly exchanges with the phosphatidylcholine in plasma. The labeled linoleic and arachidonic acids from the respective labeled phosphatidylcholines were found in the other glycerophospholipids. These transacylation processes were much more active with the arachidonoyl-labeled phosphatidylcholine than with linoleoyl-labeled phosphatidylcholine. Arachidonic acid was mainly found in the phosphatidylinositol.