Urinary adrenomedullin is related to ET-1 and salt intake in patients with mild essential hypertension

Fortunata Cuzzola, Francesca Mallamaci, Giovanni Tripepi, Saverio Parlongo, Sebastiano Cutrupi, Alessandro Cataliotti, Benedetta Stancanelli, Lorenzo Malatino, Ignazio Bellanuova, Claudio Ferri, Ferruccio Galletti, Fabiana Filigheddu, Nicola Glorioso, Pasquale Strazzullo, Carmine Zoccali

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

Adrenomedullin (ADM) infusion increases salt excretion in the rat. However, there is no evidence that this substance is related to changes in salt intake in humans. In this study we sought whether the urinary excretion rate of this autacoid is related to salt intake and by the expected changes in arterial pressure in patients with mild essential hypertension. The influence of salt intake on the renal excretion of ADM was investigated in 55 hypertensive patients in a double blind, randomized and crossover study comparing a 2-week 50 mmol/day salt intake period with a 150 mmol/day salt intake period. Twenty-four-hour ADM and endothelin-1 (ET-1) excretion rate were measured by radioimmunoassay on preextracted urinary samples (intraassay confidence variable <8%). The antibodies used in these assays had minimal ADM - ET-1 cross-reactivity (<1%). Twenty-four-hour microalbuminuria was measured by nephelometry. On univariate analysis changes in urinary ADM were significantly related to those in salt excretion (r = 0.33, P = .01) as well as to changes in urinary ET-1 (r = 0.56, P = .0001). Furthermore, changes in urinary albumin excretion were related to those in urinary ET-1 (r = 0.26, P = .05), but were independent of those in urinary ADM (P = .19). In a multiple regression model including age, sex, body mass index, and changes in systolic pressure, plasma renin activity and plasma aldosterone and urine volume, salt excretion resulted as the stronger independent predictor of urinary ADM (r = 0.33, P = .01). However, changes in urinary salt lost prediction power (P = .11) for urinary ADM when urinary ET-1 was introduced into the model. In this model (multiple r = 0.31) urinary ET-1 resulted to be the only independent predictor of urinary ADM (β = 0.56, P = .0001). This study is the first to show that the renal excretion of ADM is related to changes in salt intake and that it is tightly linked to that of ET-1. The data support the notion that these autacoids play a role in the regulation of sodium metabolism in patients with mild hypertension. The intercorrelations between ET-1, ADM, and microalbuminuria are compatible with the hypothesis that ET-1 is involved in a salt-induced increase in glomerular pressure and suggest that ADM may act as a counterregulatory factor in this situation.

Original languageEnglish (US)
Pages (from-to)224-230
Number of pages7
JournalAmerican journal of hypertension
Volume14
Issue number3
DOIs
StatePublished - 2001

Keywords

  • Adrenomedullin
  • Endothelin
  • Natriuresis
  • Plasma aldosterone
  • Plasma renin activity

ASJC Scopus subject areas

  • Internal Medicine

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