The Effect of Calcium Infusion on Renal Handling of Magnesium with Normal and Reduced Glomerular Filtration Rate

Nephron ◽  
1970 ◽  
Vol 7 (2) ◽  
pp. 131-143 ◽  
Author(s):  
J.W. Coburn ◽  
S.G. Massry ◽  
C.R. Kleeman
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Renal Handling ◽  
Calcium Infusion

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.

Excretion of progastrin products in human urine

1999 ◽  
Vol 276 (4) ◽  
pp. G985-G992 ◽  
Author(s):  
C. Palnaes Hansen ◽  
J. P. Goetze ◽  
F. Stadil ◽  
J. F. Rehfeld
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Plasma Concentrations ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Renal Handling ◽  
Renal Metabolism ◽  
Tubular Transport ◽  
Excretion Rates

The renal handling of carboxyamidated gastrins, NH2-terminal progastrin fragments, and glycine-extended gastrins was examined in healthy volunteers. The respective urinary clearances after a meal amounted to 0.09 ± 0.02%, 0.17 ± 0.04% ( P< 0.05), and 0.04 ± 0.01% ( P< 0.01) of the glomerular filtration rate. During intravenous infusion of carboxyamidated gastrin-17, progastrin fragment-(1—35), and glycine-extended gastrin-17, the respective urinary clearances amounted to 0.08 ± 0.02, 0.46 ± 0.08, and 0.02 ± 0.01%, respectively, of the glomerular filtration rate. The metabolic clearance rate of the three peptides was 24.4 ± 1.3, 6.0 ± 0.4, and 8.6 ± 0.7 ml ⋅ kg−1⋅ min−1. A maximum rate for tubular transport or degradation of the peptides could not be determined, nor was a renal plasma threshold recorded. Plasma concentrations and urinary excretion rates correlated for gastrin-17 and progastrin fragment-(1—35) ( r = 0.94 and 0.97, P < 0.001), whereas the excretion of glycine-extended gastrin diminished with increasing plasma concentrations. We conclude that renal excretion of progastrin products is negligible compared with renal metabolism and that renal handling of the peptides depends on their molecular structure. Hence, the kidneys exhibited a higher excretion of NH2-terminal progastrin fragments than of carboxyamidated and especially glycine-extended gastrins.

A Nonradioactive Iothalamate Method for Measuring Glomerular Filtration Rate and Its Use to Study the Renal Handling of Cibenzoline

1988 ◽  
Vol 10 (4) ◽  
pp. 434-437 ◽  
Author(s):  
Marcus M. Reidenberg ◽  
Beverly J. Lorenzo ◽  
Dennis E. Drayer ◽  
Jeffrey Kluger ◽  
Thomas Nestor ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Renal Handling

scholarly journals Elevation of Trimethylamine-N-Oxide in Chronic Kidney Disease: Contribution of Decreased Glomerular Filtration Rate

Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 635 ◽  
Author(s):  
Caroline C. Pelletier ◽  
Mikael Croyal ◽  
Lavinia Ene ◽  
Audrey Aguesse ◽  
Stephanie Billon-Crossouard ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Glomerular Filtration Rate ◽  
Kidney Disease ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Renal Excretion ◽  
Plasma Concentrations ◽  
Tubular Secretion ◽  
Renal Elimination ◽  
Renal Handling

Gut microbiota-dependent Trimethylamine-N-oxide (TMAO) has been reported to be strongly linked to renal function and to increased cardiovascular events in the general population and in Chronic Kidney Disease (CKD) patients. Considering the lack of data assessing renal handling of TMAO, we conducted this study to explore renal excretion and mechanisms of accumulation of TMAO during CKD. We prospectively measured glomerular filtration rate (mGFR) with gold standard methods and plasma concentrations of trimethylamine (TMA), TMAO, choline, betaine, and carnitine by LC-MS/MS in 124 controls, CKD, and hemodialysis (HD) patients. Renal clearance of each metabolite was assessed in a sub-group of 32 patients. Plasma TMAO was inversely correlated with mGFR (r2 = 0.388, p < 0.001), confirming elevation of TMAO plasma levels in CKD. TMAO clearances were not significantly different from mGFR, with a mean ± SD TMAO fractional excretion of 105% ± 32%. This suggests a complete renal excretion of TMAO by glomerular filtration with a negligible participation of tubular secretion or reabsorption, during all stages of CKD. Moreover, TMAO was effectively removed within 4 h of hemodiafiltration, showing a higher fractional reduction value than that of urea (84.9% ± 6.5% vs. 79.2% ± 5.7%, p = 0.04). This study reports a strong correlation between plasma TMAO levels and mGFR, in CKD, that can be mainly related to a decrease in TMAO glomerular filtration. Clearance data did not support a significant role for tubular secretion in TMAO renal elimination.

Renal Handling of Lithium and the Effects of Mannitol and Arginine Vasopressin in man

1995 ◽  
Vol 89 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Faruq H. Noormohamed ◽  
Ariel F. Lant
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Flow Rate ◽  
Arginine Vasopressin ◽  
Filtration Rate ◽  
Free Water ◽  
Fractional Excretion ◽  
Renal Handling ◽  
Fractional Clearance ◽  
Induced Changes

1. A study has been undertaken in six healthy male subjects to clarify whether post-proximal segments of the nephron contribute to the renal handling of lithium under conditions of maximal forced osmotic load diuresis and arginine vasopressin-induced antidiuresis. Increments in the fractional clearance of free water, as a measure of effect at the proximal tubule, were positively correlated with incremental changes in flow rate, factored for glomerular filtration rate (mean r = 0.80 ± 0.12, P < 0.001), and fractional excretion of lithium (mean r = 0.84 ± 0.06, P < 0.001). Changes in flow rate and fractional excretion of lithium were also closely correlated with one another (mean r = 0.81 ± 0.06, P < 0.001), and the mean slope of these regression lines was not significantly different from unity (1.18; 95% confidence interval 0.76–1.59). These results show that, under conditions of maximal hydration, mannitol-induced changes in proximal tubular function were closely correlated with induced changes in the fractional excretion of lithium. 2. Infusion of arginine vasopressin alone (0.5 m-units/min) caused a marked reduction in both fractional clearance of free water (10.7% ± 1.2% to −1.2% ± 0.2%, P < 0.001) and flow rate factored for glomerular filtration rate (14.0 ± 1.5 to 0.8 ± 0.2%; P < 0.001) while the fractional excretion of lithium showed only a small non-significant decrease (25.3% ± 2.0% to 23.3% ± 2.2%). A similar dissociation was noted between fluid and lithium excretion when arginine vasopressin was superimposed on mannitol infusion with reductions in the fractional clearance of free water (12.7% ± 1.0% to −0.9% ± 0.7%, P < 0.001) and flow rate (18.6% ± 1.5% to 5.7% ± 1.0%; P < 0.001), while the fractional excretion of lithium showed a significant increase (28.4% ± 1.7% to 33.1% ± 2.4%; P < 0.05). The lack of correlation between fluid and lithium excretion, in the presence of arginine vasopressin with or without mannitol, indicates that the late distal tubule and collecting duct have little or no significant capacity to reabsorb lithium. 3. These findings, taken as a whole, strengthen the view that renal tubular handling of lithium is primarily a proximal event.

Changes in inorganic phosphate excretion induced by renal arterial infusion of calcium

1963 ◽  
Vol 205 (5) ◽  
pp. 1025-1032 ◽  
Author(s):  
A. R. Lavender ◽  
Theodore N. Pullman
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Tubular Reabsorption ◽  
Water Excretion ◽  
Phosphate Excretion ◽  
Constant Rate ◽  
Calcium Infusion ◽  
Inorganic Phosphate Excretion

Calcium chloride in varying concentrations was infused at a slow and constant rate into the renal artery of one kidney in the dog. The opposite kidney served as a control. In 20 experiments, the mean glomerular filtration rate and effective renal plasma flow diminished in the infused relative to the noninfused kidneys. Mean phosphate excretion was decreased in the infused relative to the control kidneys by both a fall in filtered phosphate and a rise in the net tubular reabsorption of phosphate. Mean calcium, sodium, and water excretion did not change in the infused relative to the control kidneys during calcium infusion. The data indicate that hypercalcemia acts directly on the kidney to decrease phosphate excretion by decreasing glomerular filtration rate and increasing net tubular reabsorption of phosphate.

Renal excretion of chromium-51 chloride in the dog

1984 ◽  
Vol 246 (6) ◽  
pp. F870-F878 ◽  
Author(s):  
D. L. Donaldson ◽  
C. C. Smith ◽  
A. A. Yunice
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Intravenous Infusion ◽  
Filtration Rate ◽  
Renal Excretion ◽  
Total Plasma ◽  
Renal Handling ◽  
Pentobarbital Sodium ◽  
Clearance Studies ◽  
The Mean

To examine the renal handling of the trace element chromium, clearance studies were performed in pentobarbital sodium-anesthetized mongrel dogs following either gavage or intravenous administration of chromium-51(III) chloride. Ultrafilterable plasma chromium-51 comprised as much as 9-19% of the total plasma chromium-51 when the isotope was given by gavage but only 2-3% when given by intravenous infusion. The mean ratio of the clearance of ultrafilterable plasma chromium-51 to that of endogenous creatinine was approximately unity in all dogs [0.97 +/- 0.11 to 1.14 +/- 0.10 by gavage (n = 5); 0.84 +/- 0.05 to 0.97 +/- 0.05 intravenously (n = 4)]. Regardless of the route of administration, ultrafilterable plasma chromium-51 concentration and glomerular filtration rate appeared to be the primary determinants of renal chromium-51 excretion.

Clinical Renal Function Testing by External Double Isotope Monitoring Technique

1971 ◽  
Vol 10 (01) ◽  
pp. 16-24
Author(s):  
J. Fog Pedersen ◽  
M. Fog Pedersen ◽  
Paul Madsen
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Correlation Coefficients ◽  
Feedback System ◽  
Effective Renal Plasma Flow ◽  
Advantages And Disadvantages

SummaryAn accurate catheter-free technique for clinical determination simultaneouslyof glomerular filtration rate and effective renal plasma flow by means of radioisotopes has been developed. The renal function is estimated by the amount of radioisotopes necessary to maintain a constant concentration in the patient’s blood. The infusion pumps are steered by a feedback system, the pumps being automatically turned on when the radiation measured over the patient’s head falls below a certain preset level and turned off when this level is again readied. 131I-iodopyracet was used for the estimation of effective renal plasma flow and125I-iothalamate estimation of the glomerular filtration rate. These clearances were compared to the conventional bladder clearances and good correlation was found between these two clearance methods (correlation coefficients 0.97 and.90 respectively). The advantages and disadvantages of this new clearance technique are discussed.

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