Blood platelets and angiotensin II: angiotensin II release after platelet aggregation

Recent studies have demonstrated the presence of angiotensin II (Ang II) in human platelets. The aim of the present study was to determine whether in vitro platelet aggregation induces Ang II release. We studied 20 healthy volunteers, and found that some aggregant stimuli can cause the platelet to release this peptide. Release of Ang II was greater with thrombin (40.7%) than with ADP (29%), while N-ethylmaleimide was almost ineffective. The release of Ang II following in vitro aggregant stimuli suggests that this may be one of the mechanisms through which platelets can locally modulate vascular tone and perhaps promote atherogenesis.