Fig. 5. ATP--S induces HB-EGF release in THCE cells expressing HB-EGF-AP. (A) Cells were cultured in 6-well dishes and treated with different concentrations of ATP--S (1-100 µM) for 20 minutes. AP released into the collected medium was measured as described in Materials and Methods and expressed as relative light units (RLU). (B) Cells were stimulated with 100 µM ATP--S for indicated times post stimulation (p.s.); AP activity was measured and expressed as in A. (C) Cells were stimulated with 100 µM ADP, 100 µM ATP--S, or were extensively wounded; AP activity was measured and expressed as in A. Each RLU represents the mean ± s.e.m. (n=3). ^*P<0.05 and ^**P<0.01, significant increase in AP released into the culture medium after ATP--S treatment compared with the control.