Platelet-activating factor stimulates phosphatidylinositol turnover in human platelets.

Platelet-activating factor stimulates phosphatidylinositol turnover in human platelets as indicated by 32P]phosphatidate accumulation in platelets pre-labelled with 32P]Pi, and by 3H]phosphatidate accumulation and 3H]phosphatidylinositol loss in platelets pre-labelled with 3H]arachidonate. These effects of platelet-activating factor are direct and are independent of the production and/or release of endogenous platelet agonists such as ADP, 5-hydroxytryptamine and thromboxane A2.