Fig. 1.
ADP is involved in the accumulation of [32P]PtdIns(3,4)P2 induced by TRAP. [32P]-labeled human platelets (7.5 × 108/mL) were stimulated with 40 μmol/L TRAP in the absence or the presence of 1 U/mL apyrase (− and + in [A], • and ○ in [B] and [C]) for various periods of time. (A) Aggregation was measured as described in Materials and Methods. (B) Time course of PtdIns(3,4)P2 accumulation. (C) Time course of PtdIns(3,4,5)P3 accumulation. Lipids were analyzed using an HPLC technique as indicated in Materials and Methods. Data are from 1 representative experiment of 3 independent experiments that gave very similar results.