[Effects of platelet activating factor on release of thromboxane B2 from human granulocytes and platelets]

We investigated the effects of platelet activating factor (PAF) on the release of thromboxane (Tx) B2 from human granulocytes and platelets. Stimulation of human peripheral whole blood cells by PAF (10(-5) M) resulted in the production of TxB2 (p < 0.05). When human granulocyte suspensions (2.0 x 10(6)/ml) were stimulated by calcium ionophore A23187 (10(-5) M), TxB2 levels in the supernatant fluid increased significantly (p < 0.01). However PAF (10(-5) M) did not increase the levels of TxB2 in granulocyte suspensions. In the presence of cytochalasin B (5 micrograms/ml), PAF (10(-8) M, 10(-7) M, 10(-6) M) did not induce any significant release of TxB2 from granulocytes. The levels of TxB2 in human platelet suspensions were significantly increased by PAF (10(-5) M) stimulation (p < 0.05). These results suggest that PAF induces TxB2 release from human platelets, but it may not stimulate the production of TxB2 in human granulocytes.