The Relation between the Urinary Excretion of Inorganic Phosphate and Sodium

1971 ◽  
Vol 41 (3) ◽  
pp. 249-256 ◽  
Author(s):  
M. Fulop ◽  
P. Brazeau
Keyword(s):  
Glomerular Filtration Rate ◽  
Sodium Chloride ◽  
Urinary Excretion ◽  
Glomerular Filtration ◽  
Sodium Excretion ◽  
Inorganic Phosphate ◽  
Filtration Rate ◽  
Tubular Reabsorption ◽  
Back Pressure

1. The relation between the urinary excretion of inorganic phosphate and sodium was studied in anaesthetized dogs subjected to acute unilateral increases of ureteral back-pressure while receiving infusions of iso-osmotic sodium chloride. Under these circumstances modest increases of ureteral back-pressure, +14 to +23 cmH2O, were associated with relatively small changes of glomerular filtration rate from control values (−12.7 to +8.2%). 2. Increased ureteral back-pressure caused closely proportionate decreases of urinary phosphate and sodium excretion regardless of whether glomerular filtration rate increased, decreased or remained unchanged. When glomerular filtration rate increased or remained stable, the decreases of phosphate and sodium excretion were attributable to closely proportionate increases of tubular reabsorption of sodium and of phosphate. The increased tubular reabsorption of phosphate may be causally related to the increased tubular reabsorption of sodium.

Renal Tubular Reabsorption of Inorganic Sulfate in the Dog, as Affected by Glomerular Filtration Rate and Sodium Chloride

1956 ◽  
Vol 185 (3) ◽  
pp. 533-538 ◽  
Author(s):  
Fredrik Berglund ◽  
William D. Lotspeich
Keyword(s):  
Glomerular Filtration Rate ◽  
Sodium Chloride ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Chloride Ions ◽  
Tubular Reabsorption ◽  
Glomerular Filtrate ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular ◽  
Inorganic Sulfate

The sulfate Tm varies in the dog directly with the glomerular filtration rate. Sulfate Tm is markedly depressed by the intravenous injection of as little as 0.1 gm sodium chloride/kg body weight. Maximum depression is obtained first 50 minutes after the injection. Xylose, urea and mannitol have no effect on sulfate Tm. The effect of sodium chloride is therefore not due to an osmotic action, but seems to depend on an increased level of sodium or chloride ions in the glomerular filtrate.

ENDOGENOUS RENAL TRANSPORT OF FREE AMINO ACIDS IN INFANCY AND CHILDHOOD

PEDIATRICS ◽  
1968 ◽  
Vol 42 (3) ◽  
pp. 395-404 ◽  
Author(s):  
Johannes Brodehl ◽  
Karl Gellissen ◽  
Annemarie Jäkel
Keyword(s):  
Amino Acids ◽  
Glomerular Filtration Rate ◽  
Urinary Excretion ◽  
Glomerular Filtration ◽  
Free Amino Acids ◽  
Free Amino ◽  
Filtration Rate ◽  
Tubular Reabsorption ◽  
Renal Transport ◽  
Clearance Rates

Endogenous renal transport of free amino acids was determined in 12 infants, between the ages of 16 days and 4 months, and in 12 children, between 2 and 13 years of age. Values of the serum concentrations, urinary excretion, renal clearance rates, net tubular reabsorption, and percentage tubular reabsorption of 17 amino acids were obtained by short-term clearance studies, including the determination of the glomerular filtration rate by inulin. The amino acids were determined by ion exchange chromatography. A comparison of the values of infants and children revealed a specific feature of the kidney function in infancy. The urinary excretion of threonine, serine, proline, glycine, and alanine and the clearance rates of serine, proline, glycine, and alanine were significantly higher in infancy. The percentage tubular reabsorption of all amino acids was characteristically lower in infancy than in childhood, while the values of the net tubular reabsorption related to the glomerular filtration rate (TAA/CIn) were equal in both groups. These findings are thought to be due to a greater degree of heterogeneity of nephrons with increased glomerulotubular imbalance during the period of postnatal kidney development.

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.

scholarly journals THE STUDY OF RENOPROTECTIVE PROPERTIES OF ERYTROPOETIN DERIVATIVES ON THE KIDNEY ISCHEMIA-REPERFUSION MODEL

2018 ◽  
Vol 25 (6) ◽  
pp. 73-77 ◽  
Author(s):  
V. V. Elagin ◽  
D. A. Kostina ◽  
O. I. Bratchikov ◽  
M. V. Pokrovsky ◽  
T. G. Pokrovskaya
Keyword(s):  
Acute Kidney Injury ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Ischemia Reperfusion ◽  
Kidney Injury ◽  
Fractional Sodium Excretion ◽  
Male Wistar Rats ◽  
Microcirculatory Disorders

Aim.The research was designed to study the renoprotective properties of erythropoietin derivatives on the kidney ischemiareperfusion experimental model.Materials and methods.The renoprotective properties of asialo erythropoietin (0.4 μg/kg and 2.4 μg/kg 30 minutes before the induction of ischemia) and carbamylated darbepoetin (50 μg/kg 24 hours before the ischemic stimulus) were studied in comparison with erythropoietin and darbepoetin in a series of experiments on male Wistar rats on a 40-minute bilateral model of renal ischemia-reperfusion. The renoprotective properties were evaluated by the results of biochemical markers of acute kidney injury, the dynamics of glomerular filtration rate and fractional sodium excretion, as well as the severity of microcirculatory disorders.Results.It was found that the prophylactic use of asialo erythropoietin (dose-dependent) and carbamylated darbepoetin leads to a decrease in the serum concentration of markers of acute renal damage, an increase in the glomerular filtration rate, a decrease in fractional sodium excretion, and a decrease in microcirculatory disorders.Conclusion.Asialo erythropoietin and carbamylated darbepoetin have the pronounced renoprotective properties and are the promising agents for the prevention and treatment of acute kidney injury.

Effect of acute hypercapnia on PTH-stimulated phosphaturia in dietary Pi-deprived rat

1987 ◽  
Vol 253 (1) ◽  
pp. F34-F40 ◽  
Author(s):  
J. Guntupalli ◽  
B. Matthews ◽  
B. Carlin ◽  
E. Bourke
Keyword(s):  
Glomerular Filtration Rate ◽  
Parathyroid Hormone ◽  
Glomerular Filtration ◽  
Inorganic Phosphate ◽  
Filtration Rate ◽  
Direct Evidence ◽  
Respiratory Acidosis ◽  
Urinary Ph ◽  
Renal Handling ◽  
Per Se

The effects of respiratory acidosis on renal inorganic phosphate (Pi) handling are controversial. Clearance experiments, therefore, were performed in fasted, chronically parathyroidectomized (PTX), dietary Pi-deprived rats. The objectives were twofold: to study the effects of compensated and uncompensated hypercapnia per se on renal Pi excretion and to examine the interaction between acute hypercapnia, dietary Pi, and parathyroid hormone (PTH) on the renal handling of Pi. Acute hypercapnia increased the plasma Pi (delta 2.82 +/- 0.65 mg/dl, P less than 0.05) without altering the glomerular filtration rate (GFR). The FEPi increased (delta 7.26 +/- 0.48%, P less than 0.001) but the TRPi/GFR also increased. PTH (3 U X kg-1 X h-1) superimposed on hypercapnia resulted in a plasma Pi comparable to hypercapnia alone. The FEPi (7.56 +/- 0.78 vs. 24.43 +/- 2.20%; P less than 0.001) was higher and the TRPi/GFR (117 +/- 4 vs. 80 +/- 2 micrograms/min, P less than 0.01) lower, in the former group. PTH infusion during normocapnia resulted in a lower FEPi (0.20 +/- 0.10 vs. 24.43 +/- 2.20%, P less than 0.001) and a higher TRPi/GFR (106 +/- 2 vs. 80 +/- 2 micrograms/min, P less than 0.01) compared with PTH infusion during hypercapnia. Urinary adenosine 3',5'-cyclic monophosphate (cAMP) excretion was similar between the groups. During hypercapnia, when the extracellular acidemia was neutralized, the phosphaturic action of PTH persisted. These studies offer direct evidence that in chronically PTX, dietary Pi-deprived rats, the phosphaturic action of PTH is restored by hypercapnia per se. This effect appears to be independent of extracellular acidemia, changes in the plasma Pi and calcium, urinary pH and Na and cAMP excretion.

Renal and hemodynamic effects of losartan in conscious dogs during controlled mechanical ventilation

1999 ◽  
Vol 276 (3) ◽  
pp. F425-F432 ◽  
Author(s):  
Martin O. Krebs ◽  
Thorsten Kröhn ◽  
Willehad Boemke ◽  
Rainer Mohnhaupt ◽  
Gabriele Kaczmarczyk
Keyword(s):  
Mechanical Ventilation ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Urine Volume ◽  
Conscious Dogs ◽  
Positive End Expiratory Pressure ◽  
Arterial Blood ◽  
Controlled Mechanical Ventilation

In 12 conscious dogs, we investigated whether the angiotensin II-receptor antagonist losartan increases renal sodium excretion and urine volume during controlled mechanical ventilation (CMV) with positive end-expiratory pressure. In four experimental protocols, the dogs were extracellular volume (ECV) expanded (electrolyte solution, 0.5 ml ⋅ kg−1 ⋅ min−1iv) or not and received losartan (100 μg ⋅ kg−1 ⋅ min−1iv) or not. They breathed spontaneously during the 1st and 4th hour and received CMV with positive end-expiratory pressure (mean airway pressure 20 cmH2O) during the 2nd and 3rd hours. In the expansion group, dogs with losartan excreted ∼18% more sodium (69 ± 7 vs. 38 ± 5 μmol ⋅ min−1 ⋅ kg−1) and 15% more urine during the 2 h of CMV because of a higher glomerular filtration rate (5.3 ± 0.3 vs. 4.5 ± 0.2 ml ⋅ min−1 ⋅ kg−1) and the tubular effects of losartan. In the group without expansion, sodium excretion (2.0 ± 0.6 vs. 2.6 ± 1.0 μmol ⋅ min−1 ⋅ kg−1) and glomerular filtration rate (3.8 ± 0.3 vs. 3.8 ± 0.4 ml ⋅ min−1 ⋅ kg−1) did not change, and urine volume decreased similarly in both groups during CMV. Plasma vasopressin and aldosterone increased in both groups, and plasma renin activity increased from 4.9 ± 0.7 to 7.8 ± 1.3 ng ANG I ⋅ ml−1 ⋅ h−1during CMV in nonexpanded dogs without losartan. Mean arterial pressure decreased by 10 mmHg in nonexpanded dogs with losartan. In conclusion, losartan increases sodium excretion and urine volume during CMV if the ECV is expanded. If the ECV is not expanded, a decrease in mean arterial blood pressure and/or an increase in aldosterone and vasopressin during CMV attenuates the renal effects of losartan.

scholarly journals P27 The juvenile pig as animal model for unraveling renal drug elimination processes in children

2019 ◽  
Vol 104 (6) ◽  
pp. e28.1-e28
Author(s):  
L Dhondt ◽  
S Croubels ◽  
P De Paepe ◽  
P De Cock ◽  
M Devreese
Keyword(s):  
Animal Model ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Tubular Secretion ◽  
Tubular Reabsorption ◽  
Drug Elimination ◽  
Renal Drug Elimination

BackgroundOver the years pigs were promoted as potential animal model for humans due to their high degree of anatomical and physiological similarities with humans. Gasthuys et al. demonstrated that the maturation of the kidney function in terms of the glomerular filtration rate (GFR) in growing pigs was comparable to humans, but no data are currently available on renal plasma flow, renal tubular secretion and reabsorption.1 The aim of this pilot study was to unravel the contribution of distinct renal elimination processes in juvenile pigs and to compare with reported human values.MethodsEight seven-week-old pigs were intravenously administered a single bolus of a cocktail of following renal markers: iohexol (64.7 mg/kg body weight (BW), GFR), para-aminohippuric acid (PAH, 10 mg/kg BW, effective renal plasma flow (ERPF) and anion secretion), pindolol (0.05 mg/kg BW, cation secretion) and fluconazole (0.5 mg/kg, tubular reabsorption). Plasma and urinary concentrations were determined for PAH, pindolol and fluconazole at several time points. Only plasma concentrations were assessed for iohexol. PK modelling was performed with Phoenix® WinNonlin®.ResultsThe clearance of iohexol was 97.9 ± 16.1 ml/min/m² (mean ± SD). The ERPF, calculated as the renal clearance of PAH, was 9.5 ± 2.1 ml/min/kg. These GFR and ERPF values are approximately a factor 1.3 higher than the values observed in humans, namely 63.5–75.0 mL/min/m² and 6.5 ± 2.0 mL/min/kg.2,3 The net tubular secretion of PAH was 5.4 ± 1.8 mL/min/kg, which was comparable with the values obtained in humans (5.0 ± 1.8 mL/min/kg).3 Results for cation secretion and tubular reabsorption are not yet available (to be presented at the congress).ConclusionThe net tubular secretion of PAH was comparable between the juvenile pigs and humans. The GFR and ERPF were generally a factor 1.3 higher in juvenile pigs compared to humans.ReferencesGasthuys E., et al., Postnatal maturation of the glomerular filtration rate in conventional growing piglets as potential juvenile animal model for preclinical pharmaceutical research. Frontiers in Pharmacology 2017. 8.Schwartz GJ, Furth SL. Glomerular filtration rate measurement and estimation in chronic kidney disease. Pediatric Nephrology 2007;22(11):1839–1848.Gross AS, et al., Simultaneous administration of a cocktail of markers to measure renal drug elimination pathways: absence of a pharmacokinetic interaction between fluconazole and sinistrin, p-aminohippuric acid and pindolol. British Journal of Clinical Pharmacology 2001. 51(6):547–555.Disclosure(s)This study was funded by the Special Research Fund of Ghent University (BOF16/DOC/285).

RELATION OF GLOMERULAR FILTRATION RATE AND SODIUM TUBULAR REJECTION FRACTION TO RENAL SODIUM EXCRETION

1950 ◽  
Vol 160 (2) ◽  
pp. 306-310 ◽  
Author(s):  
D. M. Green ◽  
W. C. Bridges ◽  
A. D. Johnson ◽  
J. H. Lehman ◽  
F. Gray ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Renal Sodium Excretion

Natriuretic effect of atriopeptin III in rats with papillary necrosis

1989 ◽  
Vol 257 (5) ◽  
pp. F859-F865 ◽  
Author(s):  
J. Garcia-Estan ◽  
K. Takezawa ◽  
R. J. Roman
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Hydrostatic Pressure ◽  
Glomerular Filtration ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Renal Papilla ◽  
Papillary Necrosis ◽  
Juxtamedullary Nephron ◽  
Natriuretic Effect

This study compared the effects of atriopeptin III (AP III) on sodium excretion and renal interstitial hydrostatic pressure (RIHP) in control rats and in rats pretreated with 2-bromoethylamine (BEA) to produce papillary necrosis. In control rats, infusion of AP III (100 ng.kg-1.min-1) increased sodium excretion from 2.2 +/- 0.7 to 6.4 +/- 0.9 microeq.min-1.g kidney wt-1 and RIHP from 6.8 +/- 0.7 to 8.7 +/- 0.9 mmHg, whereas glomerular filtration rate and renal blood flow were unaltered. Similar results were obtained in rats pretreated with BEA 48 h before the experiment. In rats studied 6 wk after BEA treatment, the papilla was absent and there was atrophy of juxtamedullary nephrons. AP III did not alter sodium excretion or RIHP in this group of rats. These results indicate that 1) an intact renal papilla and/or juxtamedullary nephron population may be required for the natriuretic effect of AP III; 2) the papillary injury 48 h after BEA is not sufficient to abolish the natriuretic response to AP III; and 3) elevations in RIHP may play a role in the natriuretic response to AP III.

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