Enhanced distal absorption of potassium by magnesium-deficient rats

1985 ◽  
Vol 69 (5) ◽  
pp. 625-630 ◽  
Author(s):  
Norman L. M. Wong ◽  
Roger A. L. Sutton ◽  
Viroon Mavichak ◽  
Gary A. Quamme ◽  
John H. Dirks
Keyword(s):  
Potassium Chloride ◽  
Distal Tubule ◽  
Tubular Reabsorption ◽  
Renal Tubular Reabsorption ◽  
Potassium Secretion ◽  
Renal Tubular ◽  
Potassium Retention

1. The effect of acute potassium infusion on renal tubular reabsorption of potassium by magnesium-deficient and pair-fed control rats has been studied by the recollection micropuncture method. 2. During potassium chloride infusion, the amount of potassium remaining in the distal tubule is lower in magnesium-deficient than in pair-fed rats. This could be due to a reduction in potassium secretion or to an enhancement of potassium reabsorption. 3. The present study demonstrates enhanced renal potassium retention in the magnesium-deficient rat, and is in contrast to previous reports of renal potassium wasting in this circumstance.

Renal tubular reabsorption of calcium and sodium in primary hyperparathyroidism

1990 ◽  
Vol 123 (2) ◽  
pp. 194-202 ◽  
Author(s):  
Jan H. Kristiansen ◽  
Jens Brøchner-Mortensen ◽  
Kaj O. Pedersen ◽  
Søren Jensen ◽  
Torben Glud
Keyword(s):  
Primary Hyperparathyroidism ◽  
Proximal Tubule ◽  
Distal Tubule ◽  
Tubular Reabsorption ◽  
Positive Linear Correlation ◽  
Calcium Reabsorption ◽  
Renal Tubular Reabsorption ◽  
The Absolute ◽  
Renal Tubular ◽  
Reabsorption Rate

Abstract. Nine patients with primary hyperparathyroidism were studied to investigate the renal tubular reabsorption of calcium and sodium. Fasting serum and urine samples were analysed, and the glomerular filtration rate and the renal plasma clearance of lithium were determined simultaneously. Comparison was made with 9 ageand sex-matched normocalcemic controls. In the proximal tubule, there was a significantly higher absolute reabsorption of calcium in patients than in controls, whereas the fractional reabsorption rate of calcium did not differ between the two groups. In the distal tubule, the absolute calcium reabsorption rate was significantly higher in the patients, whereas the fractional reabsorption rate of calcium was significantly lower than in controls. In the patient group there was a significantly positive linear correlation between the increased tubular capacity for calsium reabsorption and the absolute proximal calcium reabsorption rate, but not between the increased capacity and the absolute distal calcium reabsorption rate. No significant differences were found in the renal tubular handling of sodium between patients and controls. Our results suggest that the increased capacity for tubular calcium reabsorption in primary hyperparathyroidism mainly is localized in the proximal tubule, and that the renal tubular handling of calcium and sodium in this disease differs from that in familial hypocalciuric hypercalcemia.

Effects of Parathyroid Hormone on Sodium and Calcium Transport in the Dog Nephron

1976 ◽  
Vol 51 (4) ◽  
pp. 345-351 ◽  
Author(s):  
R. A. L. Sutton ◽  
N. L. M. Wong ◽  
J. H. Dirks
Keyword(s):  
Parathyroid Hormone ◽  
Calcium Transport ◽  
Distal Tubule ◽  
Tubular Reabsorption ◽  
Puncture Site ◽  
Calcium Reabsorption ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular ◽  
Selective Enhancement ◽  
Bovine Parathyroid Hormone

1. The effect of purified bovine parathyroid hormone on renal tubular reabsorption of sodium and calcium has been studied by micropuncture in intact and recently thyroparathyroidectomized dogs. 2. Parathyroid hormone increased the rejection of sodium and calcium proportionately at the late proximal tubule in both intact and operated dogs. 3. In both groups of dogs, there was increased delivery of sodium and calcium to the distal tubule after the hormone. However, the Ca/Na ratio decreased, suggesting some selective enhancement of calcium reabsorption before the superficial distal puncture site. 4. In the final urine, the Ca/Na ratio decreased highly significantly in both groups of dogs, indicating a further selective effect of parathyroid hormone on calcium reabsorption in or beyond the distal convoluted tubule.

scholarly journals Early post-transplantation hypophosphatemia is associated with elevated FGF-23 levels

2011 ◽  
Vol 164 (5) ◽  
pp. 839-847 ◽  
Author(s):  
Andrea Trombetti ◽  
Laura Richert ◽  
Karine Hadaya ◽  
Jean-Daniel Graf ◽  
François R Herrmann ◽  
...  
Keyword(s):  
Renal Transplantation ◽  
Tubular Reabsorption ◽  
Phosphate Metabolism ◽  
Multivariate Models ◽  
Intact Pth ◽  
Post Transplantation ◽  
Estimated Gfr ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular ◽  
Fgf 23

BackgroundWe examined the hypothesis that high FGF-23 levels early after transplantation contribute to the onset of hypophosphatemia, independently of parathyroid hormone (PTH) and other factors regulating phosphate metabolism.MethodsWe measured serum phosphate levels (sPi), renal tubular reabsorption of Pi (TmPi/GFR), estimated GFR (eGFR), intact PTH (iPTH), calcitriol, intact (int) and C-terminal (Cter) FGF-23, dietary Pi intake and cumulative doses of glucocorticoids in 69 patients 12 days (95% confidence interval, 10–13) after renal transplantation.ResultsHypophosphatemia was observed in 43 (62%) of the patients 12 days after transplantation. Compared with non-hypophosphatemic subjects, their post-transplantation levels of intact and CterFGF-23 were higher (195 (108–288) vs 48 (40–64) ng/l, P<0.002 for intFGF-23; 205 (116–384) vs 81 (55–124) U/ml, P<0.002, for CterFGF-23). In all subjects, Cter and intFGF-23 correlated inversely with sPi (r=−0.35, P<0.003; −0.35, P<0.003, respectively), and TmPi/GFR (r=−0.50, P<0.001; −0.54, P<0.001, respectively). In multivariate models, sPi and TmPi/GFR were independently associated with FGF-23, iPTH and eGFR. Pre-transplant iPTH levels were significantly higher in patients developing hypophosphatemia after renal transplantation. Pre-transplant levels of FGF-23 were not associated with sPi at the time of transplantation.ConclusionIn addition to PTH, elevated FGF-23 may contribute to hypophosphatemia during the early post-renal transplant period.

Renal tubular reabsorption of trace alkaline earths compared with calcium

1965 ◽  
Vol 208 (6) ◽  
pp. 1165-1170 ◽  
Author(s):  
W. Joseph Rahill ◽  
Mackenzie Walser
Keyword(s):  
Protein Binding ◽  
Transport Mechanism ◽  
Tubular Reabsorption ◽  
Constant Infusion ◽  
Constant Power ◽  
Calcium Clearance ◽  
Renal Tubular Reabsorption ◽  
Order Of Magnitude ◽  
Alkaline Earths ◽  
Renal Tubular

Simultaneous clearances of inulin, calcium, and either Be7, Ba140, or Ra226, given by constant infusion, were measured in salt-depleted dogs or dogs undergoing mild saline, mannitol, or sulfate diuresis. Urine-to-plasma ratios of all three cations less than 0.5 were noted, suggesting that all can be actively reabsorbed. Clearances of barium and radium were correlated with calcium clearance, but the clearance of beryllium was unpredictable. Protein binding of beryllium was shown to be of the same order of magnitude as other alkaline earths when errors due to adsorption of Be7 onto containers were minimized. Protein binding of barium averaged 54%. The excreted-to-filtered ratio for barium was a constant power (.54) of the ratio for calcium. The data do not exclude the possibility that these cations are reabsorbed by a common transport mechanism with calcium.

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