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Kohno M, Hanehira T, Kano H, Horio T, Yokokawa K, Ikeda M, Minami M, Yasuanari K, Yoshikawa J

Plasma adrenomedullin concentrations in essential hypertension

Hypertension (Jan) 27:102-196 1996

Adrenomedullin, originally isolated from tissue extracts of pheocromocytoma, is a very potent vasorelaxant peptide which is also synthesized by endothelial cells where it inhibits the synthesis of endothelin-1. Kohno and coworkers measured the plasma concentration (by RIA) of this peptide in patients with various degrees of hypertension and renal damage and in control subjects. The study groups were well matched and the analytical methods employed sound and reliable. Adrenomedullin was definitely raised (above the upper limit of the normal range) in about half of the patients with clear-cut hypertension but normal in patients with "borderline" hypertension. Interestingly, plasma adrenomedullin levels were independent of arterial pressure (and unmodified by antihypertensive treatment) and uncorrelated with the degree of left ventricular hypertrophy, but strongly related to the GFR. The behaviour of circulating adrenomedullin in essential hypertension appears similar to that of endothelin-1 (see paper by the same authors on the Am J Med 1990;88,614) which also is very much dependent on renal function. The renal synthesis of endothelin increases when renal function declines. Whether raised plasma adrenomedullin is attributable to reduced renal degradation or increased synthesis is presently unknown. This stimulating paper puts into clinical perspective a new factor which may take part at vascular and renal level in the complex interplay which sets prevailing vascular tone. (Carmine Zoccali, M.D.)