The Effect of Acute Extracellular Volume Expansion on Sodium Chloride Reabsorption in the Diluting Segment in Man

1978 ◽  
Vol 54 (3) ◽  
pp. 333-336
Author(s):  
N. Ish-Shalom ◽  
J. Rapoport ◽  
C. Chaimovitz ◽  
O. S. Better
Keyword(s):  
Glomerular Filtration Rate ◽  
Sodium Chloride ◽  
Volume Expansion ◽  
Filtration Rate ◽  
Extracellular Volume ◽  
Free Water ◽  
Water Diuresis ◽  
Water Formation ◽  
Extracellular Volume Expansion ◽  
Distal Delivery

1. The effect of extracellular volume expansion (ECVE) during water diuresis, and of water diuresis alone, on the formation of free water in man was compared. 2. ECVE reduced free water formation at any given rate of distal delivery compared with water diuresis. Thus, ECVE depresses distal sodium chloride reabsorption. 3. This attenuation of free water formation occurred both when urine flow (V/100 ml glomerular filtration rate) and distal chloride delivery [(Cwater + CCl)/100 ml glomerular filtration rate] were used as the terms for distal delivery. 4. We suggest that the distal depression of sodium chloride reabsorption after ECVE is probably due to a direct inhibition of distal sodium chloride transport mechanisms, and not to the flooding of the diluting site by the poorly reabsorbable bicarbonate ion.

Renal Clearance of Fluoride in Children and Adolescents

PEDIATRICS ◽  
1985 ◽  
Vol 75 (3) ◽  
pp. 575-579
Author(s):  
Carl-Johan Spak ◽  
Ulla Berg ◽  
Jan Ekstrand
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Free Water ◽  
Tubular Secretion ◽  
Urinary Flow ◽  
Water Diuresis ◽  
Free Water Clearance ◽  
Clearance Technique

Renal function and fluoride excretion have been studied in 38 children. The children were divided into three groups according to their glomerular filtration rate: normal (92 to 136 mL/min/1.73 m2 of body surface area [BSA]), low (< 92 mL/min/1.73 m2 BSA, and super-normal (> 136 mL/min/1.73 m2 BSA). Standard clearance technique with infusion of inulin and p-aminohippuric acid during water diuresis was used. Mean renal fluoride clearance was 45.0 ± 9.8 (SD) mL/min in the group of children with normal glomerular filtration rates and 31.4 ± 8.8 mL/min in the group with low glomerular filtration rates. This difference was statistically significant. There was a close linear relationship between renal fluoride clearance and glomerular filtration rate, urinary flow, and free water clearance. The fractional fluoride excretion did not differ between the groups. About 60% of the filtered fluoride was reabsorbed. No evidence for tubular secretion exceeding the reabsorption could be found. The results suggest that children have lower renal fluoride clearance rates than adults and indicate that a moderate impairment of the renal function could lead to increased retention of fluoride.

Measurement of glomerular filtration rate in conscious unrestrained rats with inulin infused by implanted osmotic pumps

1985 ◽  
Vol 248 (5) ◽  
pp. F734-F738 ◽  
Author(s):  
J. Jobin ◽  
J. P. Bonjour
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Food Consumption ◽  
Filtration Rate ◽  
Extracellular Volume ◽  
Normal Fluid ◽  
Osmotic Minipumps ◽  
Extracellular Volume Expansion ◽  
Pump Implantation

A method is described for determining glomerular filtration rate (GFR) in conscious unrestrained rats without extracellular volume expansion. The glomerular marker used was 14C-labeled inulin infused in the minimal fluid volume of 1 microliter/h by intraperitoneally implanted osmotic minipumps. The workability, reproducibility, and precision of the technique was evaluated in sham-operated (sham) and uninephrectomized (UNI-NX) rats for 6 days. In six sham-operated rats the clearance of [14C]-inulin calculated from the plasma value obtained in a blood sample taken at 10 A.M. before food consumption was (means +/- SE): day 1 after pump implantation: 1.38 +/- 0.05; day 2: 1.27 +/- 0.05; day 3: 1.46 +/- 0.16; day 4: 1.45 +/- 0.15; day 5: 1.33 +/- 0.08; day 6: 1.38 +/- 0.11 ml/min. In six UNI-NX rats the corresponding values were: day 1: 0.88 +/- 0.04; day 2: 0.79 +/- 0.05; day 3: 0.91 +/- 0.03; day 4: 0.91 +/- 0.03; day 5: 0.83 +/- 0.06; day 6: 0.87 +/- 0.05 ml/min. When determined on day 2, 3, or 6 at 6 P.M., i.e., at the end of the food consumption period, [14C]inulin clearance was increased in all animals compared with the value determined at 10 A.M. in the fasted state. The use of implanted osmotic minipumps for delivering a glomerular marker such as [14C]inulin allows the determination of GFR in conscious unrestrained rats with normal fluid balance conditions. This method appears to be particularly appropriate for studying the influence of the intake and composition of food on GFR in physiological conditions.

A Role for Tubuloglomerular Feedback in Chronic Partial Ureteral Obstruction

Physiology ◽  
1993 ◽  
Vol 8 (2) ◽  
pp. 74-79
Author(s):  
P Morsing
Keyword(s):  
Renal Function ◽  
Arachidonic Acid ◽  
Ureteral Obstruction ◽  
Volume Expansion ◽  
Filtration Rate ◽  
Extracellular Volume ◽  
Tubuloglomerular Feedback ◽  
Arachidonic Acid Metabolites ◽  
Acid Metabolites ◽  
Extracellular Volume Expansion

Animals with partial ureteral obstruction have an inability to increase urinary output and glomerular filtration rate in response to an extracellular volume expansion. The mechanism may be a paradoxical resetting of tubuloglomerular feedback in the obstructed kidney, which impacts the roles of arachidonic acid metabolites and kinins in renal function.

Mechanism of natriuresis following intravascular and extracellular volume expansion

1969 ◽  
Vol 47 (2) ◽  
pp. 153-159 ◽  
Author(s):  
H. Sonnenberg ◽  
S. Solomon
Keyword(s):  
Blood Volume ◽  
Volume Expansion ◽  
Filtration Rate ◽  
Extracellular Volume ◽  
Extracellular Fluid ◽  
Sodium Reabsorption ◽  
Fluid Compartment ◽  
Proximal Tubular ◽  
Extracellular Volume Expansion ◽  
A Site

In clearance studies in rats, increases in filtration rate and electrolyte excretion were observed following both intravascular and extracellular fluid volume expansion. The inulin concentration ratio of proximal tubular fluid to plasma was decreased with extracellular expansion. Neither natriuresis nor fractional sodium reabsorption was related to the degree of intravascular expansion. Microperfusion studies demonstrated a decrease in proximal sodium reabsorption only when both intravascular and extravascular volumes were expanded; net sodium transport was not affected by a blood volume increase alone. From the data it is concluded that in the rat an increase in blood volume is followed by a rise of filtration rate and a fall of fractional reabsorption at a site distal to the proximal tubule, resulting in diuresis and natriuresis. If, in addition, the interstitial fluid compartment is expanded, a direct inhibition of the active transport component of proximal Na+ reabsorption occurs.

Volume expansion predominantly inhibits proximal reabsorption of NaCl rather than NaHCO3

1983 ◽  
Vol 245 (2) ◽  
pp. F272-F275 ◽  
Author(s):  
M. G. Cogan
Keyword(s):  
Sodium Chloride ◽  
Volume Expansion ◽  
Chloride Transport ◽  
Extracellular Volume ◽  
Sprague Dawley ◽  
Bicarbonate Reabsorption ◽  
Sprague Dawley Rats ◽  
Single Nephron ◽  
Extracellular Volume Expansion ◽  
Made In

The present study quantitated the effect of extracellular volume expansion on absolute proximal bicarbonate, chloride, and water reabsorption in 10 Sprague-Dawley rats. Paired free-flow micropuncture measurements were made in the plasma-replete euvolemic state and following 10% body wt isohydric, colloid-free volume expansion. Single nephron glomerular filtration rate and glomerular ultrafiltrate concentration of bicarbonate and chloride were similar in the two conditions. Volume expansion caused absolute proximal reabsorption of bicarbonate to fall by only 7% (from 987 +/- 39 to 920 +/- 53 pmol/min, P less than 0.05). This decrement in bicarbonate reabsorption was compatible with the known increase in bicarbonate permeability and backleak induced by expansion. In contrast, a marked 26% fall in absolute proximal chloride reabsorption occurred (from 1,601 +/- 147 to 1,180 +/- 149 peq/min, P less than 0.005), attributed to alteration in transcellular rather than passive sodium chloride transport. Thus, the decrease in absolute proximal volume reabsorption (from 19.7 +/- 1.0 to 16.7 +/- 1.2 nl/min, P less than 0.005) induced by volume expansion was predominantly a consequence of inhibition of sodium chloride rather than sodium bicarbonate reabsorption.

Effect of Chronic Salt and Water Loading on the Tubular Defects of a Child With Fanconi Syndrome (Cystinosis)

PEDIATRICS ◽  
1976 ◽  
Vol 58 (3) ◽  
pp. 370-377
Author(s):  
Billy S. Arant ◽  
Ira Greifer ◽  
Chester M. Edelmann ◽  
Adrian Spitzer
Keyword(s):  
Sodium Chloride ◽  
Sodium Bicarbonate ◽  
Clinical Condition ◽  
Volume Expansion ◽  
Fanconi Syndrome ◽  
Extracellular Volume ◽  
Metabolic Balance ◽  
Renal Functions ◽  
Extracellular Volume Expansion ◽  
Electrolyte Abnormalities

A male child discovered to have cystinosis and Fanconi syndrome at the age of 2 years 8 months was hospitalized repeatedly for episodes of hyponatremic, hypokalemic dehydration and acidosis. Attempts to correct the fluid and electrolyte abnormalities by increasing progressively the supplements of sodium chloride, sodium bicarbonate, and potassium chloride resulted only in an exacerbation of the symptoms. Tests of discrete renal functions and metabolic balance studies disclosed that, although all disturbances were expressions of the primary disease, their severity was enhanced considerably by the extracellular volume expansion induced by the vigorous therapy. Restriction in water intake resulted in an improvement in the renal performance and in the clinical condition.

Effect of Ca++ on renal handling of PO4 identical to: evidence for two reabsorptive mechanisms

1975 ◽  
Vol 229 (4) ◽  
pp. 901-906 ◽  
Author(s):  
MM Popovtzer ◽  
JB Robinette ◽  
KM McDonald ◽  
CK Kuruvila
Keyword(s):  
Serum Calcium ◽  
Volume Expansion ◽  
Filtration Rate ◽  
Single Injection ◽  
Extracellular Volume ◽  
Tubular Reabsorption ◽  
Renal Handling ◽  
Parathyroid Extract ◽  
Urinary Cyclic Amp ◽  
Extracellular Volume Expansion

The effect of hypercalcemia on renal handling of phosphorus was studied in parathyroidectomized rats during 1) extracellular volume expansion with normal saline (0.1 mg/100 g per min) and 2) parathyroid extract infusion (1 U/100 g per h). Hypercalcemia (serum calcium 12-15 mg/100 ml) blunted the phosphaturic response to volume expansion, both when serum calcium was raised acutely during volume expansion and when volume expansion was induced in rats with sustained hypercalcemia. These changes were not associated with significant variations in glomerular filtration rate and serum concentration of phosphorus. Hypercalcemia failed to alter the phosphaturic response and the increase in urinary cyclic AMP excretion following both continuous infusion and a single injection of parathyroid extract. These results are consistent with two components of tubular reabsorption of phosphorus. The first is suppressed by extracellular volume expansion and stimulated by hypercalcemia. The second is suppressed by parathyroid hormone and is not affected by hypercalcemia.

Reduced Renal Papillary Plasma Flow in Non-Ascitic Cirrhotic Rats

1993 ◽  
Vol 85 (2) ◽  
pp. 139-145 ◽  
Author(s):  
Noemí M. Atuchá ◽  
Tomás Quesada ◽  
Joaquín Garcia-Estañ
Keyword(s):  
Hydrostatic Pressure ◽  
Plasma Flow ◽  
Volume Expansion ◽  
Filtration Rate ◽  
Water Retention ◽  
Extracellular Volume ◽  
Isotonic Saline ◽  
Arterial Blood ◽  
Extracellular Volume Expansion ◽  
The One

1. The purpose of the present investigation was to determine whether an abnormality of the renal papillary circulation is present in a well-established model of cirrhosis without ascites (carbon tetrachloride/phenobarbital). 2. Compared with the control animals, cirrhotic rats showed a reduced diuretic (61.0 ±5.1 versus 18.0 ±2.5%) and natriuretic (67.8 ±8.3 versus 29.6 ±3.6%) response to a volume expansion (3% body weight infusion of 0.9% NaCl). The volume expansion-induced increase in renal interstitial hydrostatic pressure was also blunted in the cirrhotic rats (control 9.3 ±0.9 versus cirrhotic 6.1±1.0 mmHg) and there were no differences in mean arterial blood pressure, renal blood flow or glomerular filtration rate between control and cirrhotic animals. 3. Papillary plasma flow was determined by the 125I-albumin accumulation technique and expressed as mlmin−1100 g−1. In the basal state, papillary plasma flow was significantly lower in cirrhotic rats (59.1 ±4.4, n = 9) than in the control animals (81.8 ±6.9, n = 9). An isotonic saline expansion similar to the one described above significantly increased papillary plasma flow in control rats (108.4±9.1, n = 7) but did not change it in cirrhotic rats (60.2 ±4.9, n = 6). 4. Our results indicate the existence of a selective alteration in the renal papillary circulation in cirrhotic rats, both in the basal state and after a well-established vasodilatory stimulus. The reduced papillary plasma flow of the cirrhotic animals, probably mediated through changes in renal interstitial hydrostatic pressure, may participate in the sodium and water retention that precedes the development of ascites and may be an important mechanism mediating the blunted renal response to extracellular volume expansion.

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