Abstract
The influence of forskolin, an adenylate cyclase activator, and of dibutyryl cyclic AMP (Bt2cAMP) on the thrombin-induced [3H] glycerol incorporation into glycerolipids was investigated in human platelets. It was found that preincubation with 2.5mM of Bt2cAMP produced 2-4-fold increase in thrombin-induced incorporation into phospholipids compared to platelets activated by thrombin alone. Pretreatment with forskolin, which increased cellular cAMP content, also resulted in an increase in thrombin-stimulated [3H] glycerol incorporation into phospholipids. These findings demonstrate that a rise in platelet cAMP can accentuate thrombin-induced de novo synthesis of phospholipids from [3H] glycerol. Since the content of cellular cAMP was correlated with their ability to inhibit platelet activation monitored by serotonin release, it seems likely that glycerolipids, in particular phospholipids, biosynthesis is somehow involved in controlling platelet activation by thrombin.
