Platelet-induced inhibition of adrenomedullin secretion

Adrenomedullin is a biologically active peptide released from the vascular wall, which increases blood flow through its vasorelaxant effects and preve nts platelet activation by stimulation of nitric oxide synthesis. The prese nt study demonstrates that activated platelets suppress adrenomedullin secr etion from vascular endothelial cells by releasing a factor that was identi fied as transforming growth factor (TGF)-beta1. Adrenomedullin levels were reduced by up to 40% and this effect was completely abrogated by the additi on of latency-associated protein (LAP) or TGF-beta1-neutralizing antibody. Inhibition of adrenomedullin secretion in response to platelet aggregation may be an important mechanism in the induction of hemostasis. (C) 2001 Else vier Science B.V. All rights reserved.