Inhibitory effects of endogenous L-arginine analogues on nitric oxide synthesis in platelets: role in platelet hyperaggregability in hypertension.

1. An increase in plasma concentrations of endogenous L-arginine analogues, which are inhibitors of nitric oxide (NO) synthesis, may be involved in platelet activation and the increased risk of thrombosis in essential hypertension. Nitric oxide is synthesised in platelets from the amino acid L-arginine by inducible and constitutive isoforms of NO synthase (NOS), which leads to increased levels of cGMP.