Thrombin-induced granule secretion of FHL-5 platelets. Thrombin-mediated expression of CD62P (A) and CD63 (B) agonist on platelets was detected by flow cytometry. Diluted PRP (5 × 10⁷/mL) was stimulated with different concentrations of thrombin (0.05-1.0 U/mL; Dade Behring) in the presence of 1.25mM Gly-Pro-Arg-Pro/GPRP. Platelets were stained by monoclonal anti-CD62P antibody (CLBthromb/6-FITC, Immunotech) and anti-CD63 antibody (CLB-gran/12-FITC), respectively. Data are expressed as median of logarithmic fluorescence intensities.