Role of atrial natriuretic factor in renal adaptation to variation of salt intake in humans

1990 ◽  
Vol 258 (6) ◽  
pp. F1579-F1583
Author(s):  
A. Dal Canton ◽  
G. Romano ◽  
G. Conte ◽  
L. De Nicola ◽  
A. Caglioti ◽  
...  

This study was performed to define the extent to which atrial natriuretic factor (ANF) contributes to upregulate salt excretion in subjects eating a high-salt diet. Eight normal volunteers were first studied at low-salt diet (80 mmol NaCl/day); urinary sodium excretion (UNaV) and plasma ANF (PANF) were measured in the basal condition and during stepwise infusion of human alpha-ANF at 2, 4, 8, and 16 ng.min-1.kg-1. Then the same subjects were shifted to a high-salt diet (400 mmol/day), and UNaV and PANF were measured in the new balance condition. At low-salt diet, UNaV averaged 0.069 meq/min, and PANF averaged 21 pg/ml; infusion of human alpha-ANF raised stepwise both UNaV and PANF (means in meq/min and pg/ml, respectively, were 0.177 and 46, 0.218 and 76, 0.360 and 86, and 0.601 and 182). Infusion of ANF caused a progressive fall of plasma aldosterone and plasma renin activity. Mean UNaV and PANF at high-salt diet were 0.301 meq/min and 35 pg/ml. Thus, by increasing experimentally PANF in a low-salt diet condition to the levels occurring physiologically in a high-salt diet condition, a significant rise in UNaV is evoked, which accounts for approximately 50% of the rise of UNaV that is necessary to balance the increased salt intake.

1996 ◽  
Vol 7 (7) ◽  
pp. 1045-1051
Author(s):  
D Leosco ◽  
N Ferrara ◽  
P Landino ◽  
G Romano ◽  
S Sederino ◽  
...  

The effects of normal, low, and high dietary salt intake on basal atrial natriuretic factor plasma levels, plasma renin activity, and aldosterone were evaluated in seven young (Group 1), seven middle-aged (Group 2), and seven elderly healthy volunteers (Group 3). In all subjects, progressively higher doses of human alpha-atrial natriuretic factor were infused at low-sodium diet conditions to obtain hormone plasma values during infusion similar to those obtained in the same subjects at high-sodium diet conditions. Atrial natriuretic factor plasma values were significantly higher in Group 3 than in the other two groups at both normal- and high-salt diet conditions, and at all steps of the infusion study. At low-sodium diet conditions, peptide concentrations averaged 23.2 +/- 6.2 in Group 3, 26.2 +/- 1.9 in Group 2, and 19.1 +/- 3.9 pg/mL in Group 1 (P = not significant between groups). Hormone plasma values at high-salt diet conditions averaged 47 +/- 6.9 pg/mL in Group 1, 60 +/- 6.5 pg/mL in Group 2, and 136.3 +/- 14.6 pg/mL in Group 3. Each value was not significantly different from the corresponding value gained at an infusion step of 2 ng/min per kg in Group 1 and 2 (57.1 +/- 11.9 and 62.7 +/- 6.5 pg/mL, respectively), and of 1 ng/min per kg (139.1 +/- 22.2 pg/mL) in Group 3. At these infusion steps and at high-salt diet conditions, the urinary sodium excretion rate was, respectively, 0.185 +/- 0.02 and 0.311 +/- 0.02 mEq/min in Group 1, 0.168 +/- 0.01 and 0.300 +/- 0.02 mEq/min in Group 2, and 0.110 +/- 0.01 and 0.256 +/- 0.01 mEq/min in Group 3. Hormone infusion induced a progressive fall of plasma renin activity and aldosterone level in all groups. By experimentally increasing plasma concentrations of atrial natriuretic factor in a low-salt diet condition to the levels occurring physiologically in a high-salt diet condition, a significant rise in urinary sodium excretion rate is evoked, which accounts for 52% in young, 47% in middle-aged, and 30% in older subjects of the rise that is necessary to balance the increased salt intake.


1989 ◽  
Vol 161 (6) ◽  
pp. 1620-1623 ◽  
Author(s):  
Lony C. Castro ◽  
Chander P. Arora ◽  
Jane L. Davis ◽  
Calvin J. Hobel ◽  
Hassan Parvez

1990 ◽  
Vol 194 (3) ◽  
pp. 251-257 ◽  
Author(s):  
W. Debinski ◽  
O. Kuchel ◽  
N. T. Buu ◽  
M. Nemer ◽  
J. Tremblay ◽  
...  

1987 ◽  
Vol 65 (8) ◽  
pp. 1680-1683 ◽  
Author(s):  
H. Sonnenberg ◽  
U. Honrath ◽  
C. K. Chong ◽  
S. Milojevic ◽  
A. T. Veress

Weanling Dahl rats of the salt-sensitive and salt-resistant strains were kept either on a low salt diet for 10–15 weeks, or the diet was supplemented with 7% NaCl for the last 30 days. Animals were anesthetized and the renal responses to acute saline infusion and infusion of synthetic atrial natriuretic factor (ANF) were studied on both dietary regimens. Arterial blood pressures of sensitive and resistant groups were not different on the low salt intake. As expected, addition of dietary salt increased pressure markedly in the sensitive animals. Resistant rats also had smaller, but statistically significant, increases in pressure. On the low salt diet, salt-sensitive rats showed a larger renal response to saline infusion, whereas on the high salt diet there were no significant differences between strains. The responses to ANF infusion were not different between groups on either diet, although NaCl feeding potentiated the natriuresis and diuresis. Under the conditions of the present experiments there was, therefore, no indication that Dahl salt-sensitive rats had a relative inability to respond either to an acute saline load or to exogenous ANF administration.


2012 ◽  
Vol 13 (3) ◽  
pp. 353-359 ◽  
Author(s):  
MA Bayorh ◽  
A Rollins-Hairston ◽  
J Adiyiah ◽  
D Lyn ◽  
D Eatman

Introduction: The upregulation of cyclooxygenase (COX) expression by aldosterone (ALDO) or high salt diet intake is very interesting and complex in the light of what is known about the role of COX in renal function. Thus, in this study, we hypothesize that apocynin (APC) and/or eplerenone (EPL) inhibit ALDO/salt-induced kidney damage by preventing the production of prostaglandin E2 (PGE2). Methods: Dahl salt-sensitive rats on either a low-salt or high-salt diet were treated with ALDO (0.2 mg pellet) in the presence of EPL (100 mg/kg/day) or APC (1.5 mM). Indirect blood pressure, prostaglandins and ALDO levels and histological changes were measured. Results: Cyclooxygenase-2 (COX-2) levels were upregulated in the renal tubules and peritubular vessels after high-salt intake, and APC attenuated renal tubular COX-2 protein expression induced by ALDO. Plasma PGE2 levels were significantly reduced by ALDO in the rats fed a low-salt diet when compared to rats fed a high-salt diet. PGE2 was blocked by EPL but increased in the presence of APC. Conclusions: The beneficial effects of EPL may be associated with an inhibition of PGE2. The mechanism underlying the protective effects of EPL is clearly distinct from that of APC and suggests that these agents can have differential roles in cardiovascular disease.


2007 ◽  
Vol 113 (3) ◽  
pp. 141-148 ◽  
Author(s):  
Raymond R. Townsend ◽  
Shiv Kapoor ◽  
Christopher B. McFadden

The literature on salt intake and insulin sensitivity presents a mixed picture, as some studies have shown an increase, whereas others have shown a decrease, in insulin action as sodium intake is enhanced. In some cases, this may relate to the study of salt intake in patients with co-morbidities such as hypertension or diabetes. In the present study, we selected healthy normotensive lean volunteers who underwent a euglycaemic clamp following 6 days of a low-salt diet (20 mmol sodium daily) and, subsequently, 6 days of a high-salt diet (200 mmol sodium daily). Our results show an increase in insulin-mediated glucose disposal during euglycaemic clamp conditions that was significantly higher following the high-salt diet compared with the low-salt diet (7.41±0.41 compared with 6.11±0.40 mg·kg−1 of body weight·min−1 respectively; P=0.03). We measured calf blood flow before and during insulin infusion (no significant change after the two dietary salt interventions was detected) and plasma non-esterified fatty acids (also no significant differences were detected). We observed the expected increases in renin concentration and aldosterone activity in subjects on the low-salt diet, and also observed a significantly less increase in plasma noradrenaline concentration during euglycaemic insulin infusion following the high-salt compared with the low-salt diet. We propose that the 4–5-fold increase in serum aldosterone and the greater increase in plasma noradrenaline concentration following the low-salt intervention compared with the high-salt period may have contributed to the differences in insulin sensitivity following the adjustment in dietary sodium intake.


Cardiology ◽  
2015 ◽  
Vol 130 (4) ◽  
pp. 242-248 ◽  
Author(s):  
Yang Wang ◽  
Dan Wang ◽  
Chao Chu ◽  
Jian-Jun Mu ◽  
Man Wang ◽  
...  

Objective: The aim of our study was to assess the effects of altered salt and potassium intake on urinary renalase and serum dopamine levels in humans. Methods: Forty-two subjects (28-65 years of age) were selected from a rural community of northern China. All subjects were sequentially maintained on a low-salt diet for 7 days (3.0 g/day of NaCl), a high-salt diet for an additional 7 days (18.0 g/day of NaCl), and a high-salt diet with potassium supplementation for a final 7 days (18.0 g/day of NaCl + 4.5 g/day of KCl). Results: Urinary renalase excretions were significantly higher during the high-salt diet intervention than during the low-salt diet. During high-potassium intake, urinary renalase excretions were not significantly different from the high-salt diet, whereas they were significantly higher than the low-salt levels. Serum dopamine levels exhibited similar trends across the interventions. Additionally, a significant positive relationship was observed between the urine renalase and serum dopamine among the different dietary interventions. Also, 24-hour urinary sodium excretion positively correlated with urine renalase and serum dopamine in the whole population. Conclusions: The present study indicates that dietary salt intake and potassium supplementation increase urinary renalase and serum dopamine levels in Chinese subjects.


1999 ◽  
Vol 276 (6) ◽  
pp. R1749-R1757 ◽  
Author(s):  
Osamu Ito ◽  
Richard J. Roman

We recently reported that an enzyme of the cytochrome P-450 4A family is expressed in the glomerulus, but there is no evidence that 20-hydroxyeicosatetraenoic acid (20-HETE) can be produced by this tissue. The purpose of present study was to determine whether glomeruli isolated from the kidney of rats can produce 20-HETE and whether the production of this metabolite is regulated by nitric oxide (NO) and dietary salt intake. Isolated glomeruli produced 20-HETE, dihydroxyeicosatrienoic acids, and 12-hydroxyeicosatetraenoic acid (4.13 ± 0.38, 4.20 ± 0.38, and 2.10 ± 0.20 pmol ⋅ min−1⋅ mg protein−1, respectively) when incubated with arachidonic acid (10 μM). The formation of 20-HETE was dependent on the availability of NADPH and the[Formula: see text] of the incubation medium. The formation of 20-HETE was inhibited by NO donors in a concentration-dependent manner. The production of 20-HETE was greater in glomeruli isolated from the kidneys of rats fed a low-salt diet than in kidneys of rats fed a high-salt diet (5.67 ± 0.32 vs. 2.83 ± 0.32 pmol ⋅ min−1⋅ mg protein−1). Immunoblot experiments indicated that the expression of P-450 4A protein in glomeruli from the kidneys of rats fed a low-salt diet was sixfold higher than in kidneys of rats fed a high-salt diet. These results indicate that arachidonic acid is primarily metabolized to 20-HETE and dihydroxyeicosatrienoic acids in glomeruli and that glomerular P-450 activity is modulated by NO and dietary salt intake.


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