Phosphatidylethanol formation in human platelets: evidence for thrombin-induced activation of phospholipase D

Phosphatidylethanol formation was examined in (3H)arachidonic acid-labeled human platelets. In the presence of ethanol, thrombin induced the formation of (3H)phosphatidylethanol in a time- and concentration-dependent manner. The appearance of phosphatidylethanol did not involve de novo synthesis since no 32P radioactivity was incorporated into phosphatidylethanol in 32P-labeled platelets or in platelets that were permeabilized with saponin in the presence of 32P-ATP. The data provide evidence for the direct activation by thrombin of phospholipase D in human platelets.