Sodium Clearance Measurement

Gravimetric and sodium transport characteristics of lungs from BIO 14.6 (dystrophic) hamsters were compared with those of lungs from golden Syrian (normal) hamsters at 30 and 150 days of age. Isolated perfused lungs were used to determine lung permeability and fluid balance differences between normal and dystrophic animals at both ages. Apparent permeability-surface area products for air space-to-vascular space sodium, sucrose, and fluorescein isothiocyanate-labeled dextran fluxes were compared in the four groups of hamsters. Morphometric analysis of fixed lungs of representative hamsters from each group was also performed. Dystrophic hamsters exhibited higher lung wet-to-dry weight ratios than normal hamsters at both ages. Lungs from dystrophic hamsters were less sensitive to inhibition of sodium transport by amiloride than lungs from age-matched normal hamsters. Dystrophic hamster lungs had higher absolute permeabilities of the passively transported solutes, lower permeability values for sodium, and only one-half of the amiloride-sensitive sodium transport of lungs from age-matched normal hamsters. Differences in lung fluid balance between dystrophic and normal hamsters may be related to differences in sodium clearance.

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Ion association. VII. Dependence of calciuresis on natriuresis during sulfate infusion

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1961.201.5.769 ◽

1961 ◽

Vol 201 (5) ◽

pp. 769-773 ◽

Cited By ~ 37

Author(s):

Mackenzie Walser

Keyword(s):

Calcium Ion ◽

Sodium Excretion ◽

Ion Association ◽

Free Calcium ◽

Calcium Excretion ◽

Sodium Potassium ◽

Sulfate Ions ◽

The Relationship ◽

Complexing Anions ◽

Sodium Clearance

Sulfate was infused intravenously into dogs as the salt of sodium, potassium, or the organic amine, "tris." Calcium clearance was more closely correlated with sodium clearance than with sulfate excretion. When sodium excretion was low, little calciuresis occurred. The clearance of free calcium ions was calculated, making allowance for the electrostatic association between calcium and sulfate ions in the urine. The relationship between free calcium ion clearance and sodium clearance closely resembled that previously observed during saline or mannitol diuresis. Thus, in the absence of hypercalcemia, calcium excretion in the dog, in these experiments, is dependent primarily on the simultaneous sodium excretion, which determines free calcium ion excretion, and secondarily on the concentration of complexing anions in the urine, which determines how much additional calcium is excreted in bound form.

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Age-related differences in water and sodium handling after commercial hydration beverage ingestion

Journal of Applied Physiology ◽

10.1152/japplphysiol.01094.2018 ◽

2019 ◽

Vol 126 (4) ◽

pp. 1042-1048 ◽

Cited By ~ 2

Author(s):

S. Tony Wolf ◽

Anna E. Stanhewicz ◽

Megan M. Clarke ◽

Samuel N. Cheuvront ◽

Robert W. Kenefick ◽

...

Keyword(s):

Older Adults ◽

Young Adults ◽

Amino Acid ◽

Free Water ◽

Estimated Gfr ◽

Women Subjects ◽

Age Related ◽

Sodium Clearance ◽

Sodium Handling ◽

Better Than

Aging is associated with altered water, electrolyte, and glucose handling. Alternative beverages to those containing carbohydrate (CHO) should be considered for older adults. We hypothesized that reduced sodium (CNa+) and/or water (CH2O) clearance would underlie greater beverage retention in older compared with young adults, secondary to reduced glomerular filtration rate (GFR). We further hypothesized that amino acid (AA)- and CHO-based beverages would promote retention better than water. Over five visits, 12 young (23 ± 3 yr; 7 men, 5 women) and 12 older (67 ± 6 yr; 5 men, 7 women) subjects consumed 1 liter of distilled water or beverages with 6% CHO, 0.46 g/l Na+ [Gatorade (GAT)]; 2.5% CHO, 0.74 g/l Na+ [Pedialyte (PED)]; 5 AA, 1.04 g/l Na+ [enterade (ENT)-5]; or 8 AA, 1.38 g/l Na+ (ENT-8) over 30 min. Blood and urine were collected every hour for 4 h after ingestion; retention, CH2O, and CNa+ were calculated at 2 and 4 h. Additional calculations adjusted CH2O and CNa+ for estimated GFR (eGFR). Water yielded the lowest retention in both groups ( P ≤ 0.02). Retention was higher in older vs. young adults except for ENT-8 at 4 h ( P = 0.73). CH2O was higher for older vs. young adults for GAT at 2 h ( P < 0.01) and GAT and PED at 4 h ( P < 0.01) after ingestion but was otherwise similar between groups. CNa+ was lower in older vs. young adults except for ENT-8 ( P ≥ 0.19). Adjusting for eGFR resulted in higher CH2O for all beverages in older vs. young adults ( P < 0.05) but did not influence CNa+. Older adults may better retain beverages with less Na+ than young adults because of reduced CNa+. AA- and CHO-based electrolyte-rich beverages may similarly promote beverage retention. NEW & NOTEWORTHY Commercially available amino acid (AA)-containing beverages may provide an alternative to traditional carbohydrate (CHO)-containing beverages, particularly for older adults with attenuated water, electrolyte, and glucose handling. We compared beverage retention and free water and sodium clearance between young and older adults after ingestion of water, two CHO-based beverages, and two AA-based beverages. Our data suggest that older adults better retain beverages with less sodium compared with young adults and that AA-based and CHO-based electrolyte-containing beverages similarly promote retention.

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Renal regulation of sodium, potassium and chloride balance in single- and twin-pregnant goats

Acta Veterinaria Hungarica ◽

10.1556/avet.58.2010.2.6 ◽

2010 ◽

Vol 58 (2) ◽

pp. 199-209 ◽

Cited By ~ 1

Author(s):

Katarzyna Michałek ◽

Dorota Jankowiak ◽

Małgorzata Ożgo ◽

Wiesław Skrzypczak

Keyword(s):

Blood Plasma ◽

Filtration Rate ◽

Plasma Concentrations ◽

Chloride Ions ◽

The Other ◽

Electrolyte Balance ◽

Sodium Potassium ◽

Plasma And Urine Samples ◽

Potassium Clearance ◽

Sodium Clearance

The aim of these studies was to analyse and compare changes in selected parameters of renal function in terms of water-electrolyte balance regulation in single- and twin-pregnant goats. Clearance analyses were carried out on 16 pregnant White Improved goats (8 in single and 8 in twin gestation). Blood plasma and urine samples were analysed for the concentration of inulin, endogenous creatinine, sodium, potassium, and chlorides. It has been demonstrated that glomerular filtration rate (GFR) in the goat kidney does not change significantly during gestation. GFR recorded from the 1st week until the 20th week of gestation in twin-pregnant goats was only slightly higher compared to those observed in single-pregnant does. Blood plasma concentrations of major electrolytes, i.e. sodium, potassium and chloride ions, did not differ significantly in pregnant and non-pregnant goats, and remained within the reference values. From the very beginning of gestation, the single-pregnant goats showed increased renal potassium clearance; however, the level of sodium clearance remained stable. On the other hand, sodium clearance increased from the 2nd month of gestation in the twin-pregnant goats, while the load of excreted potassium did not change. These changes had probably resulted from varied levels of aldosterone and progesterone and their mutual proportions differing between the groups.

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Lithium clearance method and the renal response to low-dose dopamine in man: a randomized, controlled study

Clinical Science ◽

10.1042/cs0840237 ◽

1993 ◽

Vol 84 (2) ◽

pp. 237-242 ◽

Cited By ~ 10

Author(s):

Niels Vidiendal Olsen ◽

Michael Hecht Olsen ◽

Niels Fogh-Andersen ◽

Bo Feldt-Rasmussen ◽

Annelise Kamper ◽

...

Keyword(s):

Glomerular Filtration Rate ◽

Glomerular Filtration ◽

Plasma Flow ◽

Filtration Rate ◽

Low Dose ◽

Renal Plasma Flow ◽

Effective Renal Plasma Flow ◽

Lithium Clearance ◽

Clearance Studies ◽

Sodium Clearance

1. The effect of a single dose of lithium on renal function before and during intravenous infusion of dopamine (3 μg min−1 kg−1) was investigated in 12 healthy males. In a double-blind and randomized design, 450 mg or 600 mg of lithium carbonate or placebo was administered orally at 22.00 hours on three different occasions. After an overnight fast, the subjects were water-loaded and clearance studies were started at 09.00 hours with a 1 h baseline period and three 1 h periods during dopamine infusion. 2. Baseline sodium clearance with placebo was 0.65 ± 0.35 ml/min, but with lithium it increased to 1.25 ± 0.44 (P < 0.001) and 1.17 ± 0.46 ml/min (P < 0.01) after 450 and 600 mg, respectively. Urine flow rates were unchanged compared with placebo. Lithium did not significantly affect glomerular filtration rate, but both doses slightly increased effective renal plasma flow by 7% (P < 0.05) and 10% (P < 0.01), respectively. 3. The maximal natriuretic and diuretic effects of dopamine were not reduced by lithium, but the percentage increases in sodium clearance were significantly diminished after 450 mg (P < 0.01) and 600 mg (P < 0.001) of lithium. Lithium had no effect on dopamine-induced changes in effective renal plasma flow, glomerular filtration rate or osmolal clearance. Neither lithium nor dopamine influenced plasma concentrations of renin, aldosterone or atrial natriuretic peptide. 4. In conclusion, single test doses of lithium, as normally used in lithium clearance studies, increase baseline values of sodium clearance and effective renal plasma flow. Although these effects of lithium do not reduce the maximal renal responses to low-dose dopamine, they result in an underestimation of the percentage increase in sodium excretion.

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Effect of perfusate phosphate concentration on responses to PTH in isolated rat kidney

AJP Renal Physiology ◽

10.1152/ajprenal.1984.246.6.f907 ◽

1984 ◽

Vol 246 (6) ◽

pp. F907-F915

Author(s):

S. J. Scheinman ◽

R. Coulson

Keyword(s):

Glomerular Filtration Rate ◽

Filtration Rate ◽

Rat Kidney ◽

Phosphate Concentration ◽

Electrolyte Excretion ◽

Clearance Ratio ◽

Magnesium Excretion ◽

20 Nm ◽

Sodium Clearance ◽

Isolated Rat

We studied the excretion of electrolytes and adenosine 3',5'-cyclic monophosphate (cAMP) by rat kidneys perfused for 2 or 3 h at several concentrations of phosphate (Pi). Fractional phosphate excretion increased with higher perfusate Pi concentrations (up to 4.0 mM Pi) without parathyroid hormone (PTH), but no tubular maximum for phosphate reabsorption was reached. The addition of synthetic bovine 1-34 PTH (bPTH) gave a dose-related phosphaturia that depended on the perfusate Pi level. The urinary cAMP response to doses of bPTH was highly dependent on perfusate Pi concentration: with 20 nM bPTH, urinary cAMP was 211 +/- 94 pmol/ml glomerular filtration rate at 1.2 mM Pi and was 3,998 +/- 711 at 4.0 mM Pi (P less than 0.001). Without bPTH, cAMP excretion did not differ among Pi levels. Calcium-to-sodium clearance ratio rose with time in kidneys perfused without bPTH but fell with the addition of as little as 0.02 nM bPTH, regardless of Pi concentration. Variations in Pi or bPTH did not affect fractional magnesium excretion, which fell by 68% through 3 h of perfusion (P less than 0.001). These data suggest that the effects of Pi concentration on renal electrolyte excretion are consistent with changes in the filtered Pi load but that extracellular Pi concentrations dramatically alter the renal cAMP response to bPTH in the isolated perfused kidney.

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Action of Angiotensin I Converting Enzyme Inhibitor on the Control of Renal Function in the Cat

Clinical Science ◽

10.1042/cs0560365 ◽

1979 ◽

Vol 56 (4) ◽

pp. 365-371 ◽

Cited By ~ 16

Author(s):

E. J. Johns

Keyword(s):

Blood Flow ◽

Enzyme Activity ◽

Glomerular Filtration Rate ◽

Glomerular Filtration ◽

Nerve Stimulation ◽

Sodium Excretion ◽

Filtration Rate ◽

Perfusion Pressure ◽

Converting Enzyme ◽

Sodium Clearance

1. The renal responses to low level renal nerve stimulation and reduction in renal perfusion pressure within the autoregulatory range were measured before and after blockade of converting enzyme activity. Experiments were carried out using the unilaterally nephrectomized cat with the nerves of the remaining kidney acutely sectioned. 2. Renal nerves were stimulated to cause a 14% fall in blood flow for 15 min. Glomerular filtration rate was unchanged but sodium excretion and the ratio of sodium clearance to glomerular filtration rate fell significantly. 3. Renal nerve stimulation after blockade of converting enzyme activity was associated with a significant fall in glomerular filtration rate. The reductions in sodium excretion and in the ratio of sodium clearance to glomerular filtration rate were as large as in the absence of the blocking drug. 4. Reduction in renal perfusion pressure was associated with autoregulation of both renal blood flow and glomerular filtration rate but with large falls in sodium excretion and the ratio of sodium clearance to glomerular filtration rate. 5. After blockade of converting enzyme activity blood flow was still autoregulated in response to similar perfusion pressure reduction and glomerular filtration rate fell significantly. The ratio of sodium clearance to glomerular filtration rate, and sodium excretion, were reduced to the same extent as in the absence of the drug. 6. This information suggests that regulation of glomerular filtration rate associated with nerve stimulation or pressure reduction may be mediated by the intrarenal formation of angiotensin II, possibly acting at the efferent arteriole. They also indicate that angiotensin II is probably not involved in causing the increased sodium reabsorption.

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The Sodium-Retaining Effect of Renal Nerve Activity in the Cat: Role of Angiotensin Formation

Clinical Science ◽

10.1042/cs0510093 ◽

1976 ◽

Vol 51 (1) ◽

pp. 93-102 ◽

Cited By ~ 4

Author(s):

E. J. Johns ◽

Barbara A. Lewis ◽

Bertha Singer

Keyword(s):

Blood Flow ◽

Glomerular Filtration Rate ◽

Glomerular Filtration ◽

Filtration Rate ◽

Plasma Renin ◽

Renal Nerves ◽

Nerve Activity ◽

Renal Nerve ◽

Renal Nerve Activity ◽

Sodium Clearance

1. The effect of low-frequency stimulation of the renal nerves on renal function and renin release has been investigated. The experiments were performed in unilaterally nephrectomized, anaesthetized cats in which the nerves to the remaining kidney were sectioned. 2. When stimulation frequency was adjusted to reduce renal blood flow by approximately 15% for 15 min, glomerular filtration rate was hardly affected. The ratio sodium clearance/glomerular filtration rate was significantly reduced and plasma renin activity was significantly increased. 3. When the renal nerves were similarly stimulated in the presence of the β-adrenergic receptor blocking agent, propranolol, the glomerular filtration rate was significantly reduced and the rise in plasma renin activity was significantly inhibited. The reduction of sodium clearance/glomerular filtration rate was as great as in the control animals. 4. The results are consistent with the view that the maintenance of glomerular filtration rate, during renal nerve stimulation which reduced renal blood flow, may be mediated by the local generation of angiotensin. The results also suggest that angiotensin does not play an important role in the sodium retention associated with increased renal nerve activity.

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