Exaggerated Phosphaturic Response to Volume Expansion in Patients with Essential Hypertension

1975 ◽  
Vol 49 (3) ◽  
pp. 207-211 ◽  
Author(s):  
C. Chaimovitz ◽  
A. Spierer ◽  
H. Leibowitz ◽  
S. Tuma ◽  
O. S. Better
Keyword(s):  
Volume Expansion ◽  
Chloride Solution ◽  
Sodium Reabsorption ◽  
Water Diuresis ◽  
Diluting Segment ◽  
Hypertensive Patients ◽  
Reabsorptive Capacity ◽  
Proximal Tubular ◽  
Isotonic Sodium Chloride ◽  
Distal Delivery

1. Tubular handling of sodium in hypertensive patients has been evaluated with urinary phosphate excretion used as a marker for proximal tubular reabsorptive capacity. 2. Nine hypertensive patients and nine normal control subjects were studied during sustained water diuresis and the intravenous infusion of isotonic sodium chloride solution to produce volume expansion. 3. In the hypertensive patients there was exaggerated phosphaturia, natriuresis and enhanced distal delivery of sodium. Sodium reabsorption in the diluting segment was normal. 4. The enhanced distal delivery and augmented phosphaturia suggest that a decreased reabsorption of sodium in the proximal tubule is the most likely explanation for the exaggerated natriuretic response to volume expansion in hypertensive patients.

Increased Proximal Tubular Sodium Reabsorption in Hypertensive Patients with Type 2 Diabetes

1989 ◽  
Vol 6 (7) ◽  
pp. 614-620 ◽  
Author(s):  
J.-C. Mbanya ◽  
T. H. Thomas ◽  
R. Taylor ◽  
K. G. M. M. Alberti ◽  
R. Wilkinson
Keyword(s):  
Type 2 Diabetes ◽  
Sodium Reabsorption ◽  
Hypertensive Patients ◽  
Tubular Sodium Reabsorption ◽  
Proximal Tubular

Studies on Mineralocorticoid ‘Escape’ in Cirrhosis

1979 ◽  
Vol 56 (5) ◽  
pp. 401-406 ◽  
Author(s):  
S. P. Wilkinson ◽  
I. K. Smith ◽  
Helen Moodie ◽  
Lucilla Poston ◽  
R. Williams
Keyword(s):  
Extracellular Fluid ◽  
Plasma Renin ◽  
Fluid Volume ◽  
The Other ◽  
Extracellular Fluid Volume ◽  
Sodium Reabsorption ◽  
Sodium Retention ◽  
Similar Extent ◽  
Water Diuresis ◽  
Diluting Segment

1. The mineralocorticoid 9α-fluorohydrocortisone was given to 12 patients with cirrhosis without ascites. In seven an ‘escape’ from its sodium-retaining effects was observed, the other five continuing to retain sodium. 2. Changes in plasma renin activity (PRA) and inulin clearance (Cinulin) were used in the assessment of possible changes in the ‘effective’ extracellular fluid volume. PRA fell and Cinulin increased to a similar extent in each of the two groups of patients. These findings do not support the concept that the failure to show the mineralocorticoid escape in some patients with cirrhosis is due to a failure of expansion of the effective extracellular fluid volume. 3. Sodium reabsorption in the different segments of the nephron as estimated by clearance techniques under conditions of maximal water diuresis showed that the greatest changes to account for both mineralocorticoid escape and sodium retention were in the part of the nephron beyond the diluting segment.

scholarly journals The effect of volume expansion on sodium reabsorption in the diluting segment of the dog kidney

1972 ◽  
Vol 1 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Lewis J. Barton ◽  
L.Henry Lackner ◽  
Floyd C. Rector ◽  
Donald W. Seldin
Keyword(s):  
Volume Expansion ◽  
Sodium Reabsorption ◽  
Diluting Segment ◽  
Dog Kidney

Influence of volume expansion on proximal tubular sodium reabsorption in congestive heart failure

1973 ◽  
Vol 85 (1) ◽  
pp. 55-64 ◽  
Author(s):  
William M. Bennett ◽  
Grover C. Bagby ◽  
John N. Antonovic ◽  
George A. Porter
Keyword(s):  
Heart Failure ◽  
Congestive Heart Failure ◽  
Volume Expansion ◽  
Sodium Reabsorption ◽  
Tubular Sodium Reabsorption ◽  
Proximal Tubular

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.

Renal sodium reabsorption following induction of recovery from volume expansion

1977 ◽  
Vol 233 (5) ◽  
pp. F416-F420
Author(s):  
T. F. Knight ◽  
E. J. Weinman
Keyword(s):  
Urinary Excretion ◽  
Proximal Tubule ◽  
Volume Expansion ◽  
Isotonic Saline ◽  
Extracellular Fluid ◽  
Recovery Phase ◽  
Sodium Reabsorption ◽  
Distal Nephron ◽  
Renal Sodium Reabsorption ◽  
Distal Delivery

In the rat, infusion of a volume of isotonic saline equal to 2% of body weight resulted in an 82% increase in delivery of filtrate out of the proximal tubule but little or, in some animals, no change in the urinary excretion of sodium. By contrast, further degrees of volume expansion resulted in lesser increases in the distal delivery of filtrate, but were associated with a marked increase in the urinary excretion of sodium. Sixty minutes following completion of volume expansion, while the animals were still in positive sosium balance, the urinary excretion of sodium decreased 52% compared to a decrease of only 24% in the distal delivery of filtrate. During the course of progressive volume expansion and during the recovery phase, there was a dissociation between alterations in sodium reabosrption in the proximal convoluted tubule and in the whole kidney. These studies indicate that although the proximal tubule is more sensitive to changes in the extracellular fluid volume, distal nephron sites are ultimately responsible both for the natriuresis of volume expansion and the relative antinatriuresis of the recovery periods.

Single-nephron function and renal oxygen consumption during rapid volume expansion

1976 ◽  
Vol 231 (4) ◽  
pp. 1166-1172 ◽  
Author(s):  
SW Weinstein ◽  
J Szyjewicz
Keyword(s):  
Oxygen Consumption ◽  
Proximal Tubule ◽  
Volume Expansion ◽  
Ringer Solution ◽  
Sodium Reabsorption ◽  
Distal Nephron ◽  
Renal Oxygen Consumption ◽  
Single Nephron ◽  
Proximal Tubular ◽  
Renal Sodium Reabsorption

Isotonic volume expansion reduces net filtrate reabsorption in the proximal tubule while increasing it in Henle's loop. To determine the role oxidative metabolism plays in these processes, experiments were performed on rats initially hydropenic and then rapidly volume expanded with isotonic Ringer solution. Whole-kidney sodium reabsorption, oxygen consumption, and single-nephron function were measured simultaneously. During volume expansion, net renal sodium reabsorption increased concomitantly with a fall in oxygen consumption and a reduction in proximal tubular absolute filtrate reabsorption. The increase in quantity of nonreabsorbed filtrate delivered into the loop of Henle greatly exceeded the amount excreted in the urine. Thus, filtrate reabsorption by the distal nephron segments increased. These data provide evidence that acute volume expansion reduces oxygen-dependent active solute transport in the proximal tubule. The increase noted in distal nephron sodium reabsorption appears nonoxygen dependent, energized by anaerobic glycolysis or occurring passively.

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