scholarly journals Effect of sodium intake on single nephron glomerular filtration rate and sodium reabsorption in experimental uremia

1975 ◽  
Vol 8 (1) ◽  
pp. 14-20 ◽  
Author(s):  
Herbert Weber ◽  
Kang-Yann Lin ◽  
Neal S. Bricker
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Sodium Intake ◽  
Sodium Reabsorption ◽  
Single Nephron

scholarly journals Dietary Protein Intake and Single-Nephron Glomerular Filtration Rate

Nutrients ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2549 ◽  
Author(s):  
Rina Oba ◽  
Go Kanzaki ◽  
Takaya Sasaki ◽  
Yusuke Okabayashi ◽  
Kotaro Haruhara ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Creatinine Clearance ◽  
Glomerular Filtration ◽  
Dietary Protein ◽  
Protein Intake ◽  
Filtration Rate ◽  
Sodium Intake ◽  
University Hospital ◽  
Dietary Protein Intake ◽  
Single Nephron

High protein intake can increase glomerular filtration rate (GFR) in response to excretory overload, which may exacerbate the progression of kidney disease. However, the direct association between glomerular hemodynamic response at the single-nephron level and dietary protein intake has not been fully elucidated in humans. In the present study, we evaluated nutritional indices associated with single-nephron GFR (SNGFR) calculated based on corrected creatinine clearance (SNGFRCr). We retrospectively identified 43 living kidney donors who underwent enhanced computed tomography and kidney biopsy at the time of donation at Jikei University Hospital in Tokyo from 2007 to 2018. Total nephron number was estimated with imaging-derived cortical volume and morphometry-derived glomerular density. SNGFRCr was calculated by dividing the corrected creatinine clearance by the number of non-sclerosed glomeruli (NglomNSG). The mean (± standard deviation) NglomNSG/kidney and SNGFRCr were 685,000 ± 242,000 and 61.0 ± 23.9 nL/min, respectively. SNGFRCr was directly associated with estimated protein intake/ideal body weight (p = 0.005) but not with body mass index, mean arterial pressure, albumin, or sodium intake. These findings indicate that greater protein intake may increase SNGFR and lead to glomerular hyperfiltration.

Long-term Regulation of Arterial Pressure, Glomerular Filtration and Renal Sodium Reabsorption by Angiotensin II in Dogs

1980 ◽  
Vol 59 (s6) ◽  
pp. 87s-90s ◽  
Author(s):  
J. E. Hall ◽  
A. C. Guyton ◽  
M. J. Smith ◽  
T. G. Coleman
Keyword(s):  
Glomerular Filtration Rate ◽  
Angiotensin Ii ◽  
Arterial Pressure ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Sodium Intake ◽  
Sodium Balance ◽  
Sodium Reabsorption ◽  
Filtration Fraction ◽  
Plasma Aldosterone Concentration

1. This study was designed to quantify the role of angiotensin II in determining the chronic relationships between arterial pressure, renal haemodynamics and sodium excretion. 2. In six control dogs sodium balance was achieved during chronic increases in sodium intake from 5 to 495 mmol/day with small increases in arterial pressure (7mmHg), moderate increases in glomerular filtration rate (19%) and decreases in filtration fraction. Similar increases in sodium intake in dogs whose circulating levels of angiotensin II were fixed, due to a constant intravenous infusion of 4.85 pmol of angiotensin II min−1 kg−1, caused large increases in arterial pressure (42%), glomerular filtration rate (31%), filtration fraction and calculated renal sodium reabsorption above control. In six dogs whose angiotensin II formation was blocked by SQ 14 225, sodium balance at intakes of 5–80 mmol/day occurred at reduced arterial pressure, glomerular filtration rate, filtration fraction and sodium reabsorption although plasma aldosterone concentration was not substantially different from that in control dogs. At sodium intakes above 240 mmol/day arterial pressure was not altered by SQ 14 225. 3. These data indicate that during chronic variations in sodium intake angiotensin II plays a major role, independently of changes in plasma aldosterone concentration, in allowing sodium balance without large fluctuations in glomerular filtration rate or arterial pressure. The mechanism whereby angiotensin II conserves sodium chronically is through increased sodium reabsorption, since steady-state sodium reabsorption was increased by angiotensin II and decreased by SQ 14 225.

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

1975 ◽  
Vol 49 (3) ◽  
pp. 193-200 ◽  
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.

Abnormalities in glomerular function in rats developing spontaneous hypertension

1984 ◽  
Vol 246 (1) ◽  
pp. F12-F20 ◽  
Author(s):  
J. R. Dilley ◽  
C. T. Stier ◽  
W. J. Arendshorst
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Fluid Collection ◽  
Spontaneously Hypertensive ◽  
Fluid Delivery ◽  
Fluid Load ◽  
Single Nephron ◽  
Wistar Kyoto ◽  
Ultrafiltration Pressure

Clearance and micropuncture studies were conducted on 6-wk-old spontaneously hypertensive rats (SHR) of the Okamoto-Aoki strain and normotensive Wistar-Kyoto rats (WKY) under euvolemic conditions. Mean arterial pressure in SHR was elevated by 18 mmHg and their kidneys were vasoconstricted with reduced blood flow; resistances in preglomerular vessels and efferent arterioles were elevated 2.8 and 2 times, respectively, above WKY values. Whole kidney glomerular filtration rate (GFR) and single nephron glomerular filtration rate (SNGFR), based on fluid collection from either proximal or distal convolutions, were 25-30% lower in SHR. Fractional reabsorptions of fluid load by the proximal convoluted tubule (43%) and by the loop of Henle (52-55%) were similar in both groups. Accordingly, SHR exhibited less fluid delivery from the proximal convolution (8 vs. 12 nl/min) and to the distal convolution (3 vs. 5 nl/min). Glomerular dynamics in hypertensive and normotensive strains were characterized by filtration pressure disequilibrium. Estimated glomerular capillary pressure and mean effective ultrafiltration pressure were similar in SHR and WKY. SHR had a lower glomerular ultrafiltration coefficient than WKY (0.011 vs. 0.016 nl X s-1 X mmHg-1), which, combined with a lower glomerular plasma flow (41 vs. 73 nl/min), quantitatively accounted for the lower SNGFR in 6-wk-old SHR. These findings document important differences in renal function in young SHR compared with WKY that may participate in the development of hypertension.

Sodium and Water Excretion in Nephrotic Patients: Effects of Changes in Renal Haemodynamics

1990 ◽  
Vol 79 (2) ◽  
pp. 123-129 ◽  
Author(s):  
Michael Allon ◽  
Charles B. Pasque ◽  
Mariano Rodriguez
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Urine Volume ◽  
Sodium Reabsorption ◽  
Plasma Volume Expansion ◽  
Water Excretion ◽  
Significant Change

1. Eight nephrotic patients were studied in order to evaluate the effects of acute changes in renal plasma flow and glomerular filtration rate on renal solute and water handling, in the absence of plasma volume expansion. 2. The subjects were studied first after the administration of captopril, a manoeuvre that increased renal plasma flow without a significant change in glomerular filtration rate, and a second time after receiving combined therapy with captopril and ibuprofen, a manoeuvre that decreased glomerular filtration rate without a significant change in renal plasma flow. 3. After captopril therapy, despite the increase in renal plasma flow, there was no significant change in proximal sodium reabsorption (as estimated from fractional lithium reabsorption), urine volume or urine osmolality. 4. The decrease in glomerular filtration rate observed after the administration of captopril plus ibuprofen was associated with decreases in fractional excretion of sodium and urine volume, and an increase in urine osmolality. The changes in these parameters of tubular function were proportionate to the changes in glomerular filtration rate. Fractional proximal sodium reabsorption increased substantially. 5. These observations suggest that, in the absence of plasma volume expansion, an increase in renal plasma flow does not increase sodium or water excretion by the nephrotic kidney. Moreover, during acute decreases in glomerular filtration rate, glomerulotubular balance appears to be disrupted, resulting in disproportionately high rates of proximal tubule sodium reabsorption.

Effect of Urodilatin Infusion on Renal Haemodynamics, Tubular Function and Vasoactive Hormones

1997 ◽  
Vol 92 (4) ◽  
pp. 397-407 ◽  
Author(s):  
JAN Carstens ◽  
Kaare T. Jensen ◽  
Erling B. Pedersen
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Distal Part ◽  
Renal Haemodynamics ◽  
Sodium Reabsorption ◽  
Lithium Clearance ◽  
Short Term

1. The renal efficacy of urodilatin in humans has only been partly investigated. It is unknown whether intravenously infused urodilatin has an effect on sodium reabsorption in both the proximal and distal part of the nephron. 2. Twelve healthy subjects participated in this double-blind, placebo-controlled study in a crossover design. They received, in a randomized order, a short term (60 min) infusion of urodilatin in three different doses (10, 20 and 40 ng min−1 kg−1 of body weight) and placebo. Renal haemodynamics were estimated by clearance technique with radioactive tracers, and proximal tubular handling of sodium was evaluated by lithium clearance. 3. The 20 ng min−1 kg−1 dose increased the urinary sodium excretion and urinary flow rate compared with the effects of placebo. It increased the glomerular filtration rate and decreased the effective renal plasma flow. In addition, the dose increased the lithium clearance compared with placebo, but did not significantly change the fractional excretion of lithium. On the other hand, it markedly decreased the distal fractional reabsorption of sodium. It also had a suppressive effect on renin secretion. The systemic arterial blood pressure was unchanged, but the dose increased the pulse rate and the haematocrit. The highest dose (40 ng min−1 kg−1) induced a wide variation in the natriuretic and diuretic responses, probably due to a blood-pressure-lowering effect. 4. We conclude, that the urodilatin dose of 20 ng min−1 kg−1 of body weight was most efficacious in this short-term infusion study, and that it had potent natriuretic and diuretic qualities, probably due to stimulation of the glomerular filtration rate and inhibition of sodium reabsorption in the distal part of the nephron.

Micropuncture study of the superficial nephron of Perognathus penicillatus

1981 ◽  
Vol 241 (6) ◽  
pp. F612-F617
Author(s):  
E. J. Braun ◽  
D. R. Roy ◽  
R. L. Jamison
Keyword(s):  
Glomerular Filtration Rate ◽  
Proximal Tubule ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Distal Tubule ◽  
Urine Osmolality ◽  
Small Rodent ◽  
Micropuncture Study ◽  
Single Nephron ◽  
Average Body

A micropuncture study of Perognathus penicillatus, a small rodent native to the deserts of the southwestern United States was performed to evaluate the function of the superficial nephron. Data are reported for 12 animals of 17 g average body wt. Mean glomerular filtration rate was 475 +/- 73 microliter X min-1 X g kidney wt-1. Urine osmolality averaged 1,154 +/- 197 mosmol/kg H2O. Single nephron glomerular filtration rate averaged 43 nl X min-1 X g kidney wt-1 in the proximal tubule and 48 in the distal tubule, values that are not significantly different. In terms of the filtered load remaining unreabsorbed at the end of the accessible proximal tubule, the average percentages were 46 water, 48 total solute, 45 sodium, 56 phosphorus, 62 potassium, 71 magnesium, and 54 calcium. The concentrations of potassium and magnesium in fluid samples increased significantly along the proximal tubule. Approximately at the midpoint of the distal tubule, fractional delivery of water, 13.1%, was greater than that for total solute, 10%, or sodium, 7%, indicating that the intervening segment of nephron reabsorbed solute and sodium in excess of water. The function of the superficial nephron resembles that of species previously investigated except for potassium reabsorption in the proximal convoluted tubule.

Neurogenic regulation of proximal bicarbonate and chloride reabsorption

1986 ◽  
Vol 250 (1) ◽  
pp. F22-F26 ◽  
Author(s):  
M. G. Cogan
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Sprague Dawley ◽  
Electrolyte Excretion ◽  
Nerve Activity ◽  
Renal Nerve ◽  
Single Nephron ◽  
Renal Nerve Activity ◽  
Chloride Excretion

Although a change in renal nerve activity is known to alter proximal reabsorption, it is unclear whether reabsorption of NaHCO3 or NaCl or both are affected. Sprague-Dawley rats (n = 10) were studied using free-flow micropuncture techniques during euvolemia and following acute ipsilateral denervation. Glomerular filtration rate and single nephron glomerular filtration rate were stable. Absolute proximal bicarbonate reabsorption fell following denervation (933 +/- 40 to 817 +/- 30 pmol/min) with a parallel reduction in chloride reabsorption (1,643 +/- 116 to 1,341 +/- 129 peq/min). Urinary sodium, potassium, bicarbonate, and chloride excretion all increased significantly. To further assess the physiological significance of neurogenic modulation of proximal transport, other rats (n = 6) were subjected to acute unilateral nephrectomy (AUN). There is evidence that AUN induces a contralateral natriuresis (renorenal reflex) at least partially by causing inhibition of efferent renal nerve traffic. AUN caused significant changes in proximal NaHCO3 and NaCl reabsorption as well as in whole kidney electrolyte excretion in the same pattern as had denervation. Prior denervation of the remaining kidney prevented the proximal and whole kidney response to AUN (n = 6). In conclusion, depression of renal nerve activity inhibits both NaHCO3 and NaCl reabsorption in the rat superficial proximal convoluted tubule. The data are consistent with the hypothesis that changes in renal nerve activity modify whole kidney electrolyte excretion under physiological conditions at least partially by regulating proximal transport.

Sign in / Sign up

Export Citation Format

Share Document