ADRENOMEDULLIN - A NEWLY DISCOVERED HORMONE CONTROLLING FLUID AND ELECTROLYTE HOMEOSTASIS

Neural and humoral mechanisms controlling fluid and electrolyte homeos tasis employ a diverse array of physiologic mechanisms that often, whe n aberrant, are the underlying cause of disease. Behavioral, hormonal, renal, and vascular responses to volume and osmotic challenges must b e coordinated to achieve the goal of homeostasis. In recent years, it has become apparent that there exist a number of hormonal factors prod uced throughout the body that can coordinate these multiple regulatory mechanisms by complementary effects in several tissues. Thus, in addi tion to their vasoactive properties, recently characterized hormones s uch as the natriuretic peptides and the endothelins, as well as the be tter established renin-angiotensin system, exert central nervous, rena l, cardiac, and pituitary effects that regulate normal fluid and elect rolyte balance. Now a new player, adrenomedullin, has been added to th e cast, and the interplay of multiple hormonal factors involved in the physiology and pathophysiology of volume and osmotic status continues to the elucidated.