Epoprostenol (prostacyclin, PGI2) binding and activation of adenylate cyclase in platelets of diabetic and control subjects

1 The binding of epoprostenol (prostacyclin, PGI2) to isolated fractured human platelets has been studied using tritiated PGI2. 2 High and low affinity binding sites for PGI2 have been identified (Kd values = 16 and 382 nM). 3 Analysis of the prostacyclin-dependent activation of adenylate cyclase suggests that enzyme activation is mediated by the high affinity binding site. 4 Platelet PGI2 receptor binding and adenylate cyclase activation by PGI2 are unchanged in diabetic and normal human platelets. 5 This work suggests that hyperaggregability of diabetic platelets is not due to any alteration of platelet prostacyclin receptor numbers or their activation.