Renal sodium transport and oxygen consumption

1961 ◽  
Vol 201 (3) ◽  
pp. 511-516 ◽  
Author(s):  
Fredrik Kiil ◽  
Knut Aukland ◽  
Harald E. Refsum
Keyword(s):  
Oxygen Consumption ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Sodium Transport ◽  
Filtration Rate ◽  
Sodium Reabsorption ◽  
Renal Oxygen Consumption ◽  
Tubular Lumen ◽  
Oxygen Difference ◽  
Renal Oxygen

Glomerular filtration rate and renal blood flow were increased in dogs by infusion of 2% glycine and hypertonic NaCl at rates of 8 ml/min. This procedure resulted both in an increased rate of sodium reabsorption and in increased oxygen consumption. Approximately six equivalents of sodium were transported per equivalent oxygen consumed, a ratio similar to that obtained by others when glomerular filtration rate had been reduced. These observations strongly suggest that a large part of renal oxygen consumption is related to the transport of sodium. When the rate of sodium reabsorption was reduced during mannitol diuresis, arteriovenous oxygen difference decreased, but renal oxygen consumption remained unchanged. It is suggested that the active sodium transport in the proximal tubules continues at an unchanged rate during mannitol diuresis but that net reabsorption is reduced owing to increased passive influx into the tubular lumen when the transtubular concentration gradient increases. Other interpretations are discussed.

Effects of Cardiopulmonary Bypass on Renal Perfusion, Filtration, and Oxygenation in Patients Undergoing Cardiac Surgery

2017 ◽  
Vol 126 (2) ◽  
pp. 205-213 ◽  
Author(s):  
Lukas Lannemyr ◽  
Gudrun Bragadottir ◽  
Vitus Krumbholz ◽  
Bengt Redfors ◽  
Johan Sellgren ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Surgery ◽  
Oxygen Consumption ◽  
Glomerular Filtration Rate ◽  
Cardiopulmonary Bypass ◽  
Filtration Rate ◽  
Oxygen Supply ◽  
Renal Vasoconstriction ◽  
Renal Oxygen Consumption ◽  
Renal Oxygen

Abstract Background Acute kidney injury is a common complication after cardiac surgery with cardiopulmonary bypass. The authors evaluated the effects of normothermic cardiopulmonary bypass on renal blood flow, glomerular filtration rate, renal oxygen consumption, and renal oxygen supply/demand relationship, i.e., renal oxygenation (primary outcome) in patients undergoing cardiac surgery. Methods Eighteen patients with a normal preoperative serum creatinine undergoing cardiac surgery procedures with normothermic cardiopulmonary bypass (2.5 l · min−1 · m−2) were included after informed consent. Systemic and renal hemodynamic variables were measured by pulmonary artery and renal vein catheters before, during, and after cardiopulmonary bypass. Arterial and renal vein blood samples were taken for measurements of renal oxygen delivery and consumption. Renal oxygenation was estimated from the renal oxygen extraction. Urinary N-acetyl-β-d-glucosaminidase was measured before, during, and after cardiopulmonary bypass. Results Cardiopulmonary bypass induced a renal vasoconstriction and redistribution of blood flow away from the kidneys, which in combination with hemodilution decreased renal oxygen delivery by 20%, while glomerular filtration rate and renal oxygen consumption were unchanged. Thus, renal oxygen extraction increased by 39 to 45%, indicating a renal oxygen supply/demand mismatch during cardiopulmonary bypass. After weaning from cardiopulmonary bypass, renal oxygenation was further impaired due to hemodilution and an increase in renal oxygen consumption, accompanied by a seven-fold increase in the urinary N-acetyl-β-d-glucosaminidase/creatinine ratio. Conclusions Cardiopulmonary bypass impairs renal oxygenation due to renal vasoconstriction and hemodilution during and after cardiopulmonary bypass, accompanied by increased release of a tubular injury marker.

Oxygen requirement of renal Na-K-ATPase-dependent sodium reabsorption

1977 ◽  
Vol 232 (2) ◽  
pp. F152-F158 ◽  
Author(s):  
Ole M. Sejersted ◽  
Ȗystein Mathisen ◽  
Fredrik Kiil
Keyword(s):  
Oxygen Consumption ◽  
Transport System ◽  
Sodium Transport ◽  
Sodium Reabsorption ◽  
Oxygen Requirement ◽  
Aortic Constriction ◽  
Renal Oxygen Consumption ◽  
Wide Range ◽  
Before And After ◽  
Renal Oxygen

The oxygen requirement of the Na-K-ATPase-dependent sodium transport system was examined in anesthetized dogs infused with 15% mannitol-Ringer solutions at a rate of 35 ml/min. Because of renal vasodilatation and abolished autoregulation, filtered sodium (FNa) could be varied over a wide range by progressive aortic constriction. Sodium reabsorption.(RNa and renal oxygen consumption (RVo2) varied in proportion to FNa (r> 0.9). Ouabain, which inhibits Na-K-ATPases reduced RVo2 by 45 ± 6%. During subsequent aortic constriction, the ratio ΔRNa/ΔFNa averaged 0.45 (glomerulotubular balance) (r> 0.9), whereas RVo2 was not significantly altered. Comparisons of ΔRNa/ΔFNa before and after ouabain administration, indicate that about half of an increase in sodium delivery to the distal nephron is reabsorbed by the Na-K-ATPase-dependent sodium transport system and that ΔRNa/ΔRVo2 (Na/O2 ratio) of this system averages 14.5 ± 1.3. This Na/O2 ratio corresponds to 2.4 sodium ions transported per ATP dephosphorylated as found in other tissues. autoregulation; ATP; dog; glomerular filtration rate; mannitol; ouabain; renal blood flow; renal oxygen consumption Submitted on February 24, 1976

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.

Glomerular Filtration Rate and Segmental Tubular Function in the Early Phase after Transplantation/Uninephrectomy in Recipients and Their Living-Related Kidney Donors

1994 ◽  
Vol 87 (5) ◽  
pp. 519-523 ◽  
Author(s):  
Anne-Lise Kamper ◽  
Niels-Henrik Holstein-Rathlou ◽  
Svend Strandgaard ◽  
Paul Peter Leyssac ◽  
Ole Munck
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Sodium Reabsorption ◽  
Lithium Clearance ◽  
Kidney Donors ◽  
Fluid Reabsorption ◽  
Living Related ◽  
Reabsorption Rate ◽  
Sodium Clearance

1. Glomerular filtration rate and sequential tubular function were investigated in 18 adult renal transplant recipients and in their matched, adult living-related kidney donors before and 5 days after transplantation/uninephrectomy. At day 54, 13 donors and 11 recipients were re-investigated. Sixteen of these constituted eight matched pairs. This reduction in the study population was caused by the application of two withdrawal criteria. 2. In the recipients glomerular filtration rate was unchanged at day 5 and had increased to 61 ml/min at day 54 (P < 0.05). In the donors glomerular filtration rate had increased to 59 ml/min by day 5 (P < 0.01) and was unchanged at day 54. 3. In the recipients lithium clearance was unchanged at day 5 and had increased to 23 ml/min at day 54 (P < 0.01). In the donors the lithium clearance had increased by day 5 (P < 0.01). 4. In the recipients the absolute proximal fluid reabsorption rate was about 36 ml/min throughout the study period. In the donors the absolute proximal fluid reabsorption rate had increased to 42 ml/min by day 5 (P < 0.05) and increased further to 44 ml/min by day 54 (P < 0.01). 5. In the recipients sodium clearance increased from 0.54 ml/min to 2.10 ml/min at day 54 (P < 0.01). In the donors it increased from 0.64 ml/min to 0.99 ml/min at day 54 (P < 0.05). 6. Donor-recipient comparison showed that at day 54 there was no significant difference with regard to glomerular filtration rate, lithium clearance, absolute and fractional proximal fluid reabsorption rate and absolute distal sodium reabsorption rate. The sodium clearance was higher and the fractional distal sodium reabsorption rate was lower in the recipients. 7. In conclusion, the difference in function between donors and recipients at day 5 can probably be explained by the damaging effect of many inevitable factors on the graft. Fifty-four days after transplantation the function of the graft could not be distinguished from that of the remaining kidney. This suggests that the ideal homograft possesses a normal potential for compensatory hypertrophy once the effects of the initial post-operative ischaemia and toxic factors have subsided.

scholarly journals Regulation of erythropoietin production is related to proximal tubular function

1989 ◽  
Vol 256 (5) ◽  
pp. F942-F947 ◽  
Author(s):  
K. U. Eckardt ◽  
A. Kurtz ◽  
C. Bauer
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Sensor ◽  
Collecting Duct ◽  
Inhibitory Effect ◽  
Tubular Function ◽  
Sodium Reabsorption ◽  
Renal Oxygen Consumption ◽  
Proximal Tubular ◽  
Proximal Tubular Function ◽  
Renal Oxygen

Regulation of renal erythropoietin (EPO) production is based on an intrarenal oxygen sensor. Whereas the sensitivity of this oxygen sensor to variations in renal oxygen supply is well established, the influence of changes in renal oxygen consumption has not yet been elucidated. Diuretic drugs, which inhibit active sodium reabsorption, reduce tubular oxygen consumption. We therefore investigated the effects of acetazolamide, furosemide, hydrochlorothiazide, and amiloride, known to preferentially inhibit sodium reabsorption at different segments of the nephron, on hypoxia-induced EPO formation in mice. Those drugs that are considered to act mainly in the loop of Henle, distal tubule, and collecting duct (furosemide, hydrochlorothiazide, and amiloride) did not impair EPO formation. Acetazolamide on the other hand, which is thought to act predominantly at the proximal tubular site, significantly reduced EPO formation in response to normobaric hypoxia (8 and 14% O2) and functional anemia (0.1% carbon monoxide). This inhibitory effect of acetazolamide was dose dependent and correlated with the natriuresis induced. It appeared not to depend on the metabolic acidosis induced by the drug, since the simultaneous administration of sodium bicarbonate, which restored standard bicarbonate levels to normal, did not diminish the inhibitory effect of acetazolamide on EPO production. In conclusion the data suggest that the regulation of EPO production is likely to be related to proximal tubular function.

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