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Author(s): pestana, m
santos, j
santos, a
coroas, a
correia, f
serrao, p
valbuena, c
pestanaa, m
Title: Renal dopamine and salt sensitivity of blood pressure in IgA nephropathy
Issue Date: 2004
Abstract: Background: Patients with chronic glomerulonephritis exhibit salt-sensitive ( SS) hypertension. In the early stage, however, the exact characteristics are still unclear. A decrease in renal dopamine production under basal conditions or after a sodium load has been reported in a subset of patients with SS primary hypertension. Aims: The present study examined 17 untreated IgA-N patients with near-normal renal function, to determine whether salt sensitivity appears before hypertension and whether this sensitivity is related to renal dopamine production. Methods: Daily urinary excretion of dopamine, the amine precursor-L-DOPA, and metabolites was monitored in conditions of basal sodium ingestion, followed by three consecutive 5-day periods of 100, 20 and 350 mmol/day sodium intake. The sodium sensitivity index (SSI) was evaluated in each patient. In addition, the patients were considered SS when showing an increase greater than or equal to5 mm Hg in 24-hour mean BP when they changed from a 20- to a 350-mmol/day sodium diet. Results: Urinary dopamine output was lower in SS than in salt-resistant patients throughout the study (p < 0.001). This was accompanied by lower creatinine clearance values and higher urinary protein excretion in SS IgA-N patients. A strong negative relationship was observed in these 17 IgA-N patients between the SSI and the daily urinary excretion of dopamine in conditions of both 20 mmol/day sodium intake (r(2) = 0.592; p = 0.0003) and 350 mmol/day sodium diet (r(2) = 0.352; p = 0.01). However, urinary dopamine output varied appropriately throughout the study in SS patients, in agreement with changes in sodium intake. Conclusion: We conclude that in IgA-N patients, a rightward shift in the 'pressure natriuresis' can appear before hypertension and is related with a reduced renal production of dopamine. It is suggested that decreased renal dopamine synthesis in SS IgA-N patients results from acquired tubulointerstitial injury. In contrast to what has been found in SS primary hypertension, renal dopamine may behave appropriately in SS IgA-N patients, as a compensatory hormone. Copyright (C) 2004 S. Karger AG, Basel.
Subject: Ciências da Saúde, Medicina básica
Health sciences, Basic medicine
Scientific areas: Ciências médicas e da saúde::Medicina básica
Medical and Health sciences::Basic medicine
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FCNAUP - Artigo em Revista Científica Internacional
FMUP - Artigo em Revista Científica Internacional

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