[Observation on hypotensive action of adrenomedullin and its distribution in tissues]

The effect of adrenomedullin (AM) on blood pressure and tension of aortic rings were studied in normal and in either spontaneous or renal hypertensive rats (SHR/RHR). The distribution characteristics of AM in viscera was also investigated. It was found that the hypotensive action of AM was far more prominent in hypertensive than in normotensive rats. The tension lowering action on the aortic rings is dose dependent and requires the presence of endothelium. Immunohistochemistry reactivity of AM of different degrees were also found in lung, kidney and myocardium, in addition to cells of pheochromocytoma and adrenomedulla. It was suggested that AM may play an important role in the regulation of blood pressure and visceral blood circulation.