Contrasting endocrine responses to acute oral compared  with intravenous sodium loading in normal humans

There is evidence in animals and in humans for accelerated natriuresis after oral compared with intravenous sodium loading. To assess the role of atrial natriuretic peptide (ANP) as a contributory mechanism, we compared the hormonal responses to an intravenous sodium load and to the same sodium load taken orally in three separate groups of healthy subjects in balance on low, normal, or high sodium intake. On each diet, there was a trend for an early delay in sodium excretion, followed by increased natriuresis after the oral compared with intravenous sodium load. On all levels of dietary sodium intake, there was a significant (∼2-fold) increase in plasma ANP levels after intravenous saline infusion. There was a significant suppression of the renin system both after oral and intravenous sodium loading. However, there was no acute increase in plasma ANP levels after the oral sodium load, except on the very low sodium intake. This striking and unexpected observation suggests that changes in plasma ANP levels appear to play little role in the early response to an acute oral sodium load in subjects with sodium intake in the range of 150–350 mmol/day. Endocrine mechanisms for the accelerated increase in sodium excretion after oral compared with intravenous sodium loading remain to be elucidated.

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Sodium Excretion in Man, and Adaptation to a Low-Sodium Diet: Effect of Intravenous Sodium Chloride

Clinical Science ◽

10.1042/cs0570225 ◽

1979 ◽

Vol 57 (3) ◽

pp. 225-231 ◽

Cited By ~ 7

Author(s):

D. Gordon ◽

W. S. Peart

Keyword(s):

Sodium Chloride ◽

Sodium Excretion ◽

Sodium Intake ◽

Dietary Sodium ◽

Plasma Sodium ◽

Normal Male ◽

Renal Sodium Excretion ◽

Portal Monitor ◽

Intravenous Sodium ◽

Oral Sodium

1. The aim of this study was to test whether a postulated gastrointestinal or portal monitor of sodium intake plays any part in adjusting renal sodium excretion when dietary sodium is reduced. 2. Normal male subjects were given 50 mmol of sodium chloride intravenously three times daily for 3 days to replace or to supplement a constant oral intake of sodium chloride. 3. When oral sodium chloride was replaced with intravenous sodium chloride, renal sodium excretion remained constant. 4. When oral sodium chloride was kept constant, sodium administered as intravenous sodium chloride was promptly excreted in three out of four subjects. There was a delay in the increase in sodium excretion in the fourth subject. 5. Infusions containing 50 mmol of sodium chloride in 50 ml given intravenously over 22 min produced a rise in plasma sodium concentration and a fall in concentration of total plasma solids. 6. These results provide no evidence for a gastrointestinal or portal monitor of sodium intake, but do not disprove the existence of such a monitor.

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Alterations in dietary sodium intake affect cardiovagal baroreflex sensitivity

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00002.2018 ◽

2018 ◽

Vol 315 (4) ◽

pp. R688-R695 ◽

Cited By ~ 8

Author(s):

Matthew C. Babcock ◽

Michael S. Brian ◽

Joseph C. Watso ◽

David G. Edwards ◽

Sean D. Stocker ◽

...

Keyword(s):

Body Mass Index ◽

Serum Sodium ◽

Baroreflex Sensitivity ◽

Sodium Intake ◽

Plasma Osmolality ◽

Dietary Sodium ◽

High Sodium ◽

Sodium Loading ◽

Diet Intake ◽

Intravenous Sodium

High dietary sodium intake has been linked to alterations in neurally mediated cardiovascular function, but the effects of high sodium on cardiovagal baroreflex sensitivity (cBRS) in healthy adults are unknown. The purpose of this study was to determine whether high dietary sodium alters cBRS and heart rate variability (HRV) and whether acute intravenous sodium loading similarly alters cBRS and HRV. High dietary sodium (300 mmol/day, 7 days) was compared with low dietary sodium (20 mmol/day, 7 days; randomized) in 14 participants (38 ± 4 yr old, 23 ± 1 kg/m2 body mass index, 7 women). Acute sodium loading was achieved via a 23-min intravenous hypertonic saline infusion (HSI) in 14 participants (22 ± 1 yr old, 23 ± 1 kg/m2 body mass index, 7 women). During both protocols, participants were supine for 5 min during measurement of beat-to-beat blood pressure (photoplethysmography) and R-R interval (ECG). cBRS was evaluated using the sequence method. Root mean square of successive differences in R-R interval (RMSSD) was used as an index of HRV. Serum sodium (137.4 ± 0.7 vs. 139.9 ± 0.5 meq/l, P < 0.05), plasma osmolality (285 ± 1 vs. 289 ± 1 mosmol/kgH2O, P < 0.05), cBRS (18 ± 2 vs. 26 ± 3 ms/mmHg, P < 0.05), and RMSSD (62 ± 6 vs. 79 ± 10 ms, P < 0.05) were increased following high-sodium diet intake compared with low-sodium diet intake. HSI increased serum sodium (138.1 ± 0.4 vs. 141.1 ± 0.5 meq/l, P < 0.05) and plasma osmolality (286 ± 1 vs. 290 ± 1 mosmol/kgH2O, P < 0.05) but did not change cBRS (26 ± 5 vs. 25 ± 3 ms/mmHg, P = 0.73) and RMSSD (63 ± 9 vs. 63 ± 8 ms, P = 0.99). These data suggest that alterations in dietary sodium intake alter cBRS and HRV but that acute intravenous sodium loading does not alter these indexes of autonomic cardiovascular regulation.

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Dietary sodium affects systemic and renal hemodynamic response to NO inhibition in healthy humans

AJP Renal Physiology ◽

10.1152/ajprenal.1998.274.5.f914 ◽

1998 ◽

Vol 274 (5) ◽

pp. F914-F923 ◽

Cited By ~ 9

Author(s):

J. N. Bech ◽

C. B. Nielsen ◽

P. Ivarsen ◽

K. T. Jensen ◽

E. B. Pedersen

Keyword(s):

Sodium Excretion ◽

Sodium Intake ◽

Renal Hemodynamics ◽

Dietary Sodium ◽

High Sodium ◽

High Sodium Intake ◽

Healthy Humans ◽

Low Sodium ◽

Arterial Blood ◽

Relative Decrease

Animal studies have indicated that increased nitric oxide (NO) synthesis plays a significant role in the renal adaptation to increased sodium intake. To investigate the role of NO during increased sodium intake in humans, we studied the effect of acute, systemic injection of N G-monomethyl-l-arginine (l-NMMA) on renal hemodynamics [glomerular filtration rate and renal plasma flow (GFR and RPF, respectively)], urinary sodium excretion (FENa), systemic hemodynamics [mean arterial blood pressure and heart rate (MAP and HR)], and plasma levels of several vasoactive hormones in 12 healthy subjects during high (250 mmol/day) and low (77 mmol/day) sodium intake in a crossover design. The sodium diets were administered for 5 days before the l-NMMA treatments, in randomized order, with a washout period of 9 days between each diet and l-NMMA treatment. GFR and RPF were measured using the renal clearance of51Cr-labeled EDTA and125I-labeled hippuran by the constant infusion technique in clearance periods of 30-min duration. Two baseline periods were obtained, after whichl-NMMA was given (3 mg/kg over 10 min), and the effect of treatment was followed over the next five clearance periods. During high sodium intake,l-NMMA induced a more pronounced relative decrease in RPF ( P = 0.0417, ANOVA), a more pronounced relative decrease in FENa( P = 0.0032, ANOVA), and a more pronounced relative increase in MAP ( P= 0.0231, ANOVA). During low sodium intake, the effect ofl-NMMA on FENa was abolished. During low sodium intake, l-NMMA induced a sustained drop in plasma renin (31 ± 5 vs. 25 ± 5 μU/ml, P < 0.001), which was not seen during high sodium intake. The data indicate that increased production of NO is an important part of the adaptation to increased dietary sodium intake in healthy humans, with respect to renal hemodynamics, sodium excretion, and the secretion of renin.

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Gastrointestinal control of sodium excretion in sodium-depleted conscious rabbits

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1976.230.6.1504 ◽

1976 ◽

Vol 230 (6) ◽

pp. 1504-1508 ◽

Cited By ~ 28

Author(s):

RM Carey ◽

Smith ◽

EM Ortt

Keyword(s):

Gastrointestinal Tract ◽

Sodium Excretion ◽

Sodium Diet ◽

Low Sodium Diet ◽

Low Sodium ◽

Renal Sodium Excretion ◽

Sodium Loading ◽

Conscious Rabbits ◽

Intravenous Sodium ◽

Oral Sodium

Recent studies of sodium-depleted rabbits have shown that oral sodium loading is followed by greater natriuresis than intravenous sodium loading. The present study was undertaken to determine if this is dependent on differences in aldosterone excretion. Rabbits in balance on a low-sodium diet were given bolus doses of sodium either orally or intravenously. Those receiving oral sodium responded with a greater natriuresis than those receiving it intravenously. No differences in aldosterone excretion were demonstrated after oral or intravenous sodium repletion. Rabbits given large doses of exogenous aldosterone continued to excrete more sodium after oral than after intravenous repletion. This study demonstrates that in rabbits the gastrointestinal tract functions to regulate renal sodium excretion and that the mechanism is independent of aldosterone.

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Effect of sodium intake on gene expression and plasma levels of ANF in rats

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1988.255.2.h245 ◽

1988 ◽

Vol 255 (2) ◽

pp. H245-H249

Author(s):

A. L. Lattion ◽

J. F. Aubert ◽

J. P. Fluckiger ◽

J. Nussberger ◽

B. Waeber ◽

...

Keyword(s):

Gene Expression ◽

Plasma Levels ◽

Sodium Intake ◽

Dietary Sodium ◽

Dot Blot ◽

High Sodium ◽

Sodium Diet ◽

Low Sodium Diet ◽

Sodium Loading ◽

High Sodium Diet

The effect of short- and long-term sodium loading and sodium restriction on the gene expression as well as on circulating plasma levels of atrial natriuretic factor (ANF) was evaluated in normotensive Wistar rats. These rats were fed either a low-, a regular-, or a high-sodium diet (regular diet and 1% saline as drinking fluid) and studied after 1 and 3 wk. The ANF mRNA was determined in pooled atria and ventricles of the different groups of rats, using the dot-blot technique. Plasma ANF levels were measured with a radioimmunoassay. After 1 wk on the high-sodium diet, ANF mRNA was increased in right atria and ventricles together with circulating ANF levels when compared with animals maintained for the same period on a low-sodium diet. After 3 wk on the various diets, the differences in cardiac ANF mRNA and in plasma ANF levels had disappeared. Gene expression of ANF was also looked for in different areas of the brain, lung, thyroid, adrenals, and the kidney; no hybridization was detected in any of these organs. These data suggest that in rats, the transcription of the ANF gene and peptide release in enhanced only during short-term adaptation to dietary sodium loading.

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Abstract P106: Effects of Aldosterone Excess and Sodium on Dipping Patterns in Resistant Hypertensive Patients

Hypertension ◽

10.1161/hyp.68.suppl_1.p106 ◽

2016 ◽

Vol 68 (suppl_1) ◽

Author(s):

Charles German

Keyword(s):

Blood Pressure ◽

Ambulatory Blood Pressure ◽

Sodium Excretion ◽

Sodium Intake ◽

Large Body ◽

Dietary Sodium ◽

Hypertensive Patients ◽

Nocturnal Hypertension ◽

High Sodium ◽

Cardiovascular Morbidity And Mortality

Background: High dietary sodium intake and aldosterone excess have been independently linked to increased cardiovascular morbidity and mortality. In addition, a large body of literature indicates that aldosterone excess contributes importantly to antihypertensive treatment resistance and is associated with higher 24- hour ambulatory blood pressure (BP) levels. Objective: This study was designed to determine if high dietary sodium intake, and hyperaldosteronism combine to mediate the development of abnormal diurnal BP patterns including nocturnal hypertension and dipping BP patterns. Methods: A single-center cohort of 326 African American (AA) and Caucasian resistant hypertensive patients were prospectively evaluated by assessing 24-hr urinary aldosterone (UAldo), plasma renin activity (PRA), sodium (UNa + ) levels, and 24-hr ambulatory blood pressure monitoring (ABPM). Daytime, night-time, and 24-hr BP and dipping patterns were determined. High sodium excretion was defined as UNa + = 200 mEq/24hr and hyperaldosteronism was defined as UAldo = 12 μg/24hr and PRA ≤ 1 ng/ml/hr. Results: There was no difference in ABPM and dipping patterns when comparing the normal versus high sodium group. However, patients without high sodium excretion had better nocturnal (p=0.024) and 24- hour BP control (p=0.036). Furthermore, there was no difference in ABPM patterns when comparing patients with high versus normal sodium excretion with hyper versus non- hyperaldosteronism. Interestingly, in the group with hyperaldosteronism, patients with normal sodium excretion had improved dipping patterns, but only in the dipper group (p=0.016). Conclusions: High dietary sodium intake contributes to increased nocturnal hypertension and poor 24-h BP control, but there does not seem to be a significant relationship between hyperaldosteronism and high dietary sodium intake. This data suggests that improvements in dietary sodium intake will lead to better control of nighttime BP and 24-h BP control and therefore reduces the risk of cardiovascular disease. Further studies are underway comparing these relationships in males versus females, and AAs versus Caucasians.

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Is socio-demographic status, body mass index, and consumption of food away from home associated with high sodium intake among adults in Malaysia?: findings from the Malaysian Community Salt Survey (MyCoSS)

Journal of Health Population and Nutrition ◽

10.1186/s41043-021-00236-z ◽

2021 ◽

Vol 40 (S1) ◽

Author(s):

Ruhaya Salleh ◽

Shubash Shander Ganapathy ◽

Norazizah Ibrahim Wong ◽

Siew Man Cheong ◽

Mohamad Hasnan Ahmad ◽

...

Keyword(s):

Body Mass Index ◽

Logistic Regression ◽

Body Mass ◽

Sodium Intake ◽

Daily Intake ◽

Dietary Sodium ◽

Cooking Methods ◽

High Sodium ◽

High Sodium Intake ◽

Meal Consumption

Abstract Background Studies have shown that having away from home meals contributes to high sodium intake among young people and those who lived in urban areas. This study aimed to determine the association between dietary sodium intake, body mass index, and away from home meal consumption behaviour among Malaysian adults. Methods MyCoSS was a cross-sectional household survey involving 1440 adults age 18 years and above. This study utilized stratified cluster sampling to obtain a nationally representative sample. Data was collected between October 2017 and March 2018. Socio-demographic information, dietary assessment using food frequency questionnaire (FFQ), and away from home meal consumption were assessed through a face-to-face interview by trained health personnel. Descriptive analysis and logistic regression were applied to identify the association of socioeconomic status and away from home meal consumption with dietary sodium intake. Results A total of 1032 participants completed the FFQ, with a mean age of 48.8 + 15.6 years. Based on the FFQ, slightly over half of the participants (52.1%) had high sodium intake. Results showed that 43.6% of participants consumed at least one to two away from home meals per day, while 20.8% of them had their three main meals away from home. Participants aged less than 30 years old were the strongest predictor to consume more sodium (adjusted OR: 3.83; 95%CI: 2.23, 6.58) while those of Indian ethnicity had significantly lower sodium intake. Surprisingly, having three away from home meals per day was not associated with high dietary sodium intake, although a significant association (crude OR; 1.67, 95% CI: 1.19, 2.35) was found in the simple logistic regression. Obese participants were less likely to have high dietary sodium intake compared with the normal BMI participants in the final model. Conclusion Over half of the participants consumed sodium more than the recommended daily intake, especially those who consumed three away from home meals. However, there was no significant association between high sodium intake and having three away from home meals per day. The promotion of healthy cooking methods among the public must continue to be emphasized to reduce the dietary sodium intake among Malaysian adults.

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Higher Sodium Intake Assessed by 24 Hour Urinary Sodium Excretion Is Associated with Non-Alcoholic Fatty Liver Disease: The PREVEND Cohort Study

Journal of Clinical Medicine ◽

10.3390/jcm8122157 ◽

2019 ◽

Vol 8 (12) ◽

pp. 2157 ◽

Cited By ~ 1

Author(s):

Eline H. van den Berg ◽

Eke G. Gruppen ◽

Hans Blokzijl ◽

Stephan J.L. Bakker ◽

Robin P.F. Dullaart

Keyword(s):

Insulin Resistance ◽

Liver Disease ◽

Fatty Liver ◽

Sodium Excretion ◽

Fatty Liver Disease ◽

Sodium Intake ◽

Dietary Sodium ◽

Model Assessment ◽

Alcoholic Fatty Liver ◽

Alcoholic Fatty Liver Disease

A higher sodium intake is conceivably associated with insulin resistant conditions like obesity, but associations of non-alcoholic fatty liver disease (NAFLD) with a higher sodium intake determined by 24 hours (24 h) urine collections are still unclear. Dietary sodium intake was measured by sodium excretion in two complete consecutive 24 h urine collections in 6132 participants of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) cohort. Fatty Liver Index (FLI) ≥60 and Hepatic Steatosis Index (HSI) >36 were used as proxies of suspected NAFLD. 1936 (31.6%) participants had an FLI ≥60, coinciding with the increased prevalence of type 2 diabetes (T2D), metabolic syndrome, hypertension and history of cardiovascular disease. Sodium intake was higher in participants with an FLI ≥60 (163.63 ± 61.81 mmol/24 h vs. 136.76 ± 50.90 mmol/24 h, p < 0.001), with increasing incidence in ascending quartile categories of sodium intake (p < 0.001). Multivariably, an FLI ≥60 was positively associated with a higher sodium intake when taking account for T2D, a positive cardiovascular history, hypertension, alcohol intake, smoking and medication use (odds ratio (OR) 1.54, 95% confidence interval (CI) 1.44–1.64, p < 0.001). Additional adjustment for the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) diminished this association (OR 1.30, 95% CI 1.21–1.41, p < 0.001). HSI >36 showed similar results. Associations remained essentially unaltered after adjustment for body surface area or waist/hip ratio. In conclusion, suspected NAFLD is a feature of higher sodium intake. Insulin resistance-related processes may contribute to the association of NAFLD with sodium intake.

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Effect of Proportional Reduction of Sodium Intake on the Adaptive Increase in Glomerular Filtration Rate/Nephron and Potassium and Phosphate Excretion in Chronic Renal Failure in the Rat

Clinical Science ◽

10.1042/cs0490193 ◽

1975 ◽

Vol 49 (3) ◽

pp. 193-200 ◽

Cited By ~ 2

Author(s):

C. H. Espinel

Keyword(s):

Renal Failure ◽

Glomerular Filtration Rate ◽

Chronic Renal Failure ◽

Glomerular Filtration ◽

Sodium Excretion ◽

Filtration Rate ◽

Sodium Intake ◽

Dietary Sodium ◽

Control Group ◽

Phosphate Excretion

1. The influence of dietary sodium intake on the glomerular filtration rate (GFR/nephron) and potassium and phosphate excretion was examined at three stages of progressive chronic renal failure produced in rats by sequential partial nephrectomies. 2. The adaptive increased sodium excretion per nephron in the control group receiving a constant sodium intake did not occur in the experimental group that had a gradual reduction of dietary sodium in direct proportion to the fall in GFR. 3. Despite the difference in sodium excretion, the increase in GFR/nephron, the daily variation in the amount of potassium and phosphate excreted, the increase in potassium and phosphate excretion per unit nephron, and the plasma potassium and phosphate concentrations were the same in the two groups. 4. The concept of ‘autonomous adaptation’ in chronic renal failure is presented.

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