ADRENOMEDULLIN - A NEW HYPOTENSIVE PEPTIDE

Properties of adrenomedullin We have identified a novel hypotensive pe ptide, adrenomedullin, in human pheochromocytoma extract It has potent and long-lasting vasodilatory effects in several vascular systems. In addition to adrenomedullin, another hypotensive peptide, proadrenomed ullin-derived peptide (PAMP), was also found to be processed from the adrenomedullin precursor. PAMP inhibits neural transmission at periphe ral sympathetic nerve endings, although adrenomedullin directly dilate s vascular smooth muscle. Possible involvement in pathogenesis Althoug h initially isolated from human pheochromocytoma tissue, adrenomedulli n messenger RNA is highly expressed in several peripheral organs, incl uding cardiovascular tissues. Adrenomedullin and PAMP are both synthes ized and secreted from vascular smooth muscle and endothelial cells, a nd they participate in circulation control through different mechanism s. Taken together with the presence of adrenomedullin-specific recepto rs on vascular smooth muscle cells and the significant increase in pla sma immunoreactive adrenomedullin levels in patients with hypertension , renal failure and congestive heart failure, adrenomedullin may be in volved in the pathogenesis of these diseases.