Adrenomedullin in Hypertension and Other Diseases of Cardiovascular System

Abstract

Adrenomedullin was originally isolated from pheochromocytoma cells, but it is also produced and secreted by cardiovascular system, including heart, lung, aorta, vascular smooth muscle cells and endothelial cells. It is a potent vasodilator peptide consisting of 52 amino acids and it belongs to the calcitonin gene-related peptide (CGRP) superfamily. ADM receptors have always been closely associated with receptors for the related peptide CGRP, but there are receptors with higher affinity for ADM than CGRP. ADM have been shown to elevate cAMP levels in various tissue and cells. Moreover, it has also been shown that ADM dilates regional vascular bed not only in cAMP-dependent mechanism but also an NO/cGMP mechanism may be involved in. Plasma ADM levels are typically in the lower picomolar range in normal humans, and there are many factors that increase its levels. The role of ADM in the cardiovascular and endocrine regulation hasn’t been fully elucidated yet. It is clear, however, that exogenous ADM has powerful vasodilator and natriuretic actions. ADM levels are increased in patients with hypertension, renal disease and heart failure in proportion to the clinical severity of these disorders. Moreover, it has been reported that ADM may play a role in the pathogenesis of essential and secondary hypertension characterized by excessive catecholamine and aldosterone secretion.