Effect of calcitonin on calcium and magnesium transport in rat nephron

1980 ◽  
Vol 238 (6) ◽  
pp. E573-E578 ◽  
Author(s):  
G. A. Quamme
Keyword(s):  
Calcium Concentration ◽  
Transport Model ◽  
Distal Tubule ◽  
Urinary Calcium ◽  
Plasma Calcium ◽  
Loop Of Henle ◽  
Plasma Calcium Concentration ◽  
Calcium And Magnesium ◽  
Magnesium Excretion

Renal calcium and magnesium reabsorption was investigated in young, thyroparathyroidectomized rats receiving synthetic salmon calcitonin. Kidney and tubular function was assessed by clearance and in vivo microperfusion techniques, respectively. Calcitonin reduced urinary calcium and magnesium excretion that was attributed to increased reabsorption within the loop of Henle. This enchanced reabsorption was independent of parathyroid hormone; however, it is contingent on a decline in plasma calcium concentration. Prevention of hypocalcemia by CaCl2 infusion in rats acutely administered calcitonin resulted in loop function comparable to animals not receiving the hormone. Calcitonin had little effect on proximal tubule or distal tubule electrolyte reabsorption. These results are consistent with a transport model for calcium and magnesium in the loop of Henle involving a contraluminal transfer step modulated by absolute extracellular calcium or magnesium. Furthermore, these studies suggest that the discrepancies present in the literature concerning renal effects of calcitonin on electrolyte reabsorption are due to variations in observed hormone action, namely, the effect on plasma calcium concentration.

scholarly journals STANNIECTOMY INCREASES RENAL MAGNESIUM AND CALCIUM EXCRETION IN FRESHWATER NORTH AMERICAN EELS (ANGUILLA ROSTRATA)

1993 ◽  
Vol 181 (1) ◽  
pp. 107-118
Author(s):  
D. G. Butler
Keyword(s):  
North American ◽  
Calcium Concentration ◽  
Urinary Calcium ◽  
Plasma Calcium ◽  
Magnesium Concentration ◽  
Calcium Excretion ◽  
Plasma Calcium Concentration ◽  
Magnesium Excretion ◽  
Plasma Magnesium ◽  
American Eels

The corpuscles of Stannius are linked to the renal transport of magnesium in freshwater North American eels. The urinary magnesium concentration and rate of magnesium excretion increased 3 days after the corpuscles had been removed, a trend which continued throughout a 14 day observation period. There was no overall change in urine flow rates except for a brief 50 % reduction 2 days after stanniectomy. Plasma magnesium concentrations drifted downward after stanniectomy. In contrast, plasma calcium concentrations increased significantly within 2 days following stanniectomy and they continued to increase thereafter. Urinary calcium concentrations and the rate of urinary calcium excretion increased 7 days after stanniectomy, implying that the renal response was subject to the increase in plasma calcium concentration: the urine/plasma calcium ratio remained constant. Even though the urinary calcium concentration increased after stanniectomy, the increase in urinary magnesium concentration was proportionally greater.

Effect of differing concentrations of parathyroid hormone on rat renal electrolyte excretion

1982 ◽  
Vol 243 (5) ◽  
pp. F514-F517
Author(s):  
S. Carney ◽  
L. Thompson
Keyword(s):  
Parathyroid Hormone ◽  
Calcium Concentration ◽  
Fold Increase ◽  
Urinary Calcium ◽  
Plasma Calcium ◽  
Calcium Excretion ◽  
Physiological Concentration ◽  
Phosphate Excretion ◽  
Plasma Calcium Concentration ◽  
Magnesium Excretion

Urinary clearance studies were performed on acutely thyroparathyroidectomized rats to study the effect of a range of parathyroid hormone (PTH) concentrations on renal electrolyte transport. PTH 0.1 U, prime and per hour, significantly increased the plasma calcium concentration, yet fractional calcium excretion was increased by 47.5% and inorganic phosphate excretion remained unaltered. PTH 1 U produced a similar increase in the plasma calcium concentration. However, urinary calcium excretion was unchanged when compared with control animals and a small phosphaturia occurred (from 0.1 +/- 0.1 to 0.8 +/- 0.2%; P less than 0.05). PTH 10 U decreased fractional calcium excretion by 50% and increased fractional phosphate excretion from 0.4 +/- 02. to 19.4 +/- 1.7% (P less than 0.01). Changes in urinary magnesium excretion were similar to those of calcium, being increased with the lowest PTH concentration yet decreased with a 100-fold increase in PTH concentration. These data suggest that PTH, at a low physiological concentration that acts on bone, does not directly alter renal electrolyte handling. High physiological concentrations of PTH, however, produce a brisk phosphaturia and reduce calcium and magnesium excretion. A reappraisal of the accepted role of PTH on renal calcium conservation is therefore required.

Effects of Intraluminal sulfate on electrolyte transfers along the perfused rat nephron

1981 ◽  
Vol 59 (2) ◽  
pp. 122-130 ◽  
Author(s):  
Gary A. Quamme
Keyword(s):  
Proximal Tubule ◽  
Chloride Transport ◽  
Distal Tubule ◽  
Phosphate Transport ◽  
Loop Of Henle ◽  
Magnesium Transport ◽  
Calcium And Magnesium ◽  
A Site ◽  
Distal Delivery

Superficial nephrons were perfused in vivo to determine the effect of intraluminal sulfate (1–20 mM) on electrolyte reabsorption in the rat with special reference to calcium and magnesium transport. This technique allowed us the opportunity of investigating separate electrolyte transfers without alteration of extrarenal influences. The major amount of perfused sulfate was absorbed in the proximal tubule with little absorption distal to the late proximal collection site. Phosphate transport was not affected by high luminal sulfate concentrations indicating distinct reabsorptive mechanisms for these two anions. Intraluminal sulfate significantly inhibited calcium and magnesium reabsorption in the proximal tubule, loop of Henle, and superficial distal tubule, in distinction to modest effects on sodium transport in these nephron segments. Chloride transport was not altered. The inhibition of divalent cation transfer was not quantitively similar in the different tubule segments. Small amounts of sulfate completely inhibited proximal calcium and magnesium reabsorption with little effect on transport within the loop of Henle. Enhanced distal delivery of sulfate significantly inhibited calcium and magnesium reabsorption in the distal tubule, a site where the sulfate anion is not reabsorbed. These results demonstrate the importance of distal delivery of anionic ligands capable of forming nonreabsorbable complexes. Thus distal calcium and magnesium transport may be greatly modified by proximal control of anion reabsorption.

Effect of furosemide on calcium and magnesium transport in the rat nephron

1981 ◽  
Vol 241 (4) ◽  
pp. F340-F347 ◽  
Author(s):  
G. A. Quamme
Keyword(s):  
Ethacrynic Acid ◽  
Distal Tubule ◽  
Electrolyte Transport ◽  
Loop Of Henle ◽  
Transport Function ◽  
Magnesium Transport ◽  
Henle's Loop ◽  
Calcium And Magnesium ◽  
Single Tubules

Superficial tubules were perfused in vivo to determine the effect of intraluminal furosemide on electrolyte transport in the loop of Henle and distal tubule of the rat with special reference to calcium and magnesium reabsorption. in vivo perfusion of single tubules allowed us the opportunity to investigate separate electrolyte transfers with altering the corticomedullary concentration gradient within the kidney. Intraluminal furosemide (3 X 10(-6) and 3 X 10(-5) M) resulted in proportionately greater calcium and magnesium inhibition relative to sodium and chloride in Henle's loop. Furosemide had little effect on transport function within the perfused superficial distal tubule. Distal calcium and magnesium reabsorption was dependent on their respective deliveries to this segment. Parathyroid hormone increased fractional calcium and magnesium reabsorption in Henle's loop and the distal tubule in the presence of intraluminal furosemide. These results are consistent with a luminal effect of furosemide in the loop of Henle that inhibits calcium and magnesium transport to a greater degree than sodium chloride. Intraluminal ethacrynic acid (10(-4) M) or its cysteine complex had no effect on electrolyte transport in the perfused rat nephron.

Treatment of Severe Hypercalcemia in Primary Hyperparathyroidism with Aminopropylidene Diphosphonate

1992 ◽  
Vol 8 (4) ◽  
pp. 155-157
Author(s):  
Harold W. de Valk ◽  
Anton K.M. Bartelink ◽  
Onno J.J. Cluysenaer ◽  
Matthieu M. Tjoeng
Keyword(s):  
Primary Hyperparathyroidism ◽  
Calcium Concentration ◽  
Extracellular Fluid ◽  
Urinary Calcium ◽  
Plasma Calcium ◽  
Cardiac Conduction ◽  
Calcium Excretion ◽  
Hypercalcemic Crisis ◽  
Severe Hypercalcemia ◽  
Plasma Calcium Concentration

Objective: To test the clinical usefulness and potency for decreasing plasma calcium concentration of an intravenously administered diphosphonate (aminopropylide diphosphonate [APD]) in a patient with hypercalcemic crisis secondary to primary hyperparathyroidism, unresponsive to hydration and furosemide, and who was ineligible for surgery because of cardiac conduction defects. Design: Case report. Setting: Referred care setting. Intervention: The patient received APD 15 mg/d, dissolved in 100 mL of isotonic NaCl 0.9% and infused in one hour. Main Outcome Measure: Plasma calcium concentration. Results: The patient's plasma calcium concentration fell considerably in a few days. The concomitant decrease in urinary calcium excretion indicates that this fall is caused by a decreased entry of calcium to the extracellular fluid and not to increased renal calcium excretion. After nine days, a parathyroid adenoma was removed; plasma calcium concentration remained normal during the following three years. Conclusions: APD is a useful adjunct to medical therapy in patients with hypercalcemic crisis secondary to primary hyperparathyroidism.

The Effects of Synthetic Human and Salmon Calcitonins on Electrolyte Excretion in the Rat

1972 ◽  
Vol 42 (2) ◽  
pp. 129-137 ◽  
Author(s):  
C. C. Williams ◽  
E. W. Matthews ◽  
Jane M. Moseley ◽  
I. MacIntyre
Keyword(s):  
Salmon Calcitonin ◽  
Urinary Calcium ◽  
Plasma Calcium ◽  
Human Calcitonin ◽  
Slight Effect ◽  
Electrolyte Excretion ◽  
Therapeutic Implications ◽  
Small Doses ◽  
Calcium And Magnesium ◽  
Magnesium Excretion

1. The effects on renal electrolyte excretion of human and salmon synthetic calcitonins were studied in the rat. 2. As little as 50 ng of salmon calcitonin produced an increase in sodium excretion, but human calcitonin in doses up to 15 μg had only a slight effect. 3. Small doses of both hormones decreased urinary calcium and magnesium. Larger doses of salmon calcitonin produced less depression of calcium and magnesium excretion even in the presence of a greater fall in plasma calcium. 4. The mechanisms responsible for these effects and the possible therapeutic implications are discussed.

USE OF TERIPARATIDE IN A FOUR YEAR OLD PATIENT WITH AUTOSOMAL DOMINANT HYPOCALCAEMIA

2016 ◽  
Vol 101 (9) ◽  
pp. e2.63-e2 ◽  
Author(s):  
Andy Fox ◽  
Rodney Gilbert
Keyword(s):  
Calcium Concentration ◽  
Autosomal Dominant ◽  
Urinary Calcium ◽  
Plasma Calcium ◽  
Urinary Calcium Excretion ◽  
Calcium Excretion ◽  
Calcium Sensing Receptor ◽  
Calcium Supplements ◽  
Calcium Sensing ◽  
Plasma Calcium Concentration

AimWe report the effective use of the synthetic parathyroid hormone (PTH) teriparatide to treat a 4 year old boy with autosomal dominant hypocalcaemia.BackgroundAutosomal Dominant hypocalcaemia is characterised by hypocalcaemia with a lack of parathyroid hormone (PTH) response and inappropriately high urinary calcium excretion. It is caused by gain-of-function mutations in the extracellular calcium sensing receptor which then “over-reads” the extracellular fluid concentration of calcium resulting in suppression of PTH secretion. This then reduces PTH-mediated calcium reabsorption in the distal nephron. Treatment of hypocalcaemia with vitamin D analogues and calcium supplements results in further increases in urinary calcium concentrations, frequently causing nephrocalcinosis and progressive renal damage.Our four year old male patient presented in the neonatal period with seizures secondary to hypocalcaemia and low PTH levels. He suffered repeated seizures with associated tetany. Treatment with alfaclacidol and calcium supplements was able to provide seizure control, however episodes of tetany continued. A heterozygous, activating mutation of the extracellular calcium sensing receptor (c.2528C>A; p.Ala843Glu) was confirmed at age 2. The treatment caused significant hypercalciuria and nephrocalcinosis with a reduction in GFR to 73 ml/mim/m.2 Continuing this therapy would have resulted in end stage kidney disease requiring dialysis/transplantation. The decision was made to try treatment with PTH in order to raise the plasma calcium concentration while minimising the increase in urinary calcium excretion.Funding for treatment was approved by specialised commissioning and treatment was commenced at a dose of 0.4 microg/kg BD.AdministrationTeriparatide is only available in a prefilled pen (Forsteo®) delivering 20 microg in 80 microlitre per dose. Following discussions with the pharmacy team at Great Ormond Street Hospital for Sick Children a protocol was developed to allow these set doses to be diluted prior to administration. By diluting the 20 microg dose to 0.5 ml in a 1 ml syringe a solution containing 40 microg/ml was obtained.OutcomeTreatment was started at 3.66 years of age. Pre-treatment adjusted plasma calcium concentration was 1.96 mmol/L and the urinary calcium excretion was 0.11 mmol/kg/day (normal<0.1). After 5 days of treatment the patient felt very much better and had more energy. The adjusted plasma calcium concentration had risen to 2.09 mmol/L and the urinary calcium excretion had fallen to 0.045 mmol/kg/day.Over the following 9 months the dose of alfacalcidol was reduced from 600 nanograms per day to 300 nanograms per day and calcium supplements were reduced from 16 mmol four times per day to zero. The teriparatide dose was increased from an initial dose of 2 microgram twice daily to 6 microgram twice daily. The plasma calcium has remained above 2 mmol/L apart from a period where further weaning of the alfacalcidol dose was attempted.Rather to our surprise, the patient did not experience symptoms of hypercalcaemia with plasma calcium concentrations within the normal range. His muscle power and tone has increased.We conclude that teriparatide is a useful agent for treating patients with gain-of-function mutations of the calcium-sensing receptor/autosomal dominant hypocalcaemia

ABOLITION OF MAGNESIUM-INDUCED HYPOCALCAEMIA BY ACUTE THYRO-PARATHYROIDECTOMY IN THE CAT

1970 ◽  
Vol 64 (1) ◽  
pp. 150-158 ◽  
Author(s):  
S. Pors Nielsen
Keyword(s):  
Sodium Chloride ◽  
Flow Rate ◽  
Magnesium Chloride ◽  
Calcium Concentration ◽  
Plasma Calcium ◽  
Magnesium Concentration ◽  
Isotonic Sodium Chloride ◽  
Plasma Calcium Concentration ◽  
High Concentrations ◽  
Plasma Magnesium

ABSTRACT Intravenous infusion of isotonic magnesium chloride into young cats with a resultant mean plasma magnesium concentration of 7.7 meq./100 g protein was followed by a significant lowering of the plasma calcium concentration in 90 minutes. The rate of decrease of plasma calcium is consistent with the hypothesis that calcitonin is released by magnesium in high concentrations. There was no decrease in the plasma calcium concentration in cats of the same weight thyroparathyroidectomized 60 min before an identical magnesium chloride infusion or an infusion of isotonic sodium chloride at the same flow rate. The hypercalciuric effect of magnesium could not account for the hypocalcaemic effect of magnesium. Plasma magnesium concentration during magnesium infusion into cats with an intact thyroid-parathyroid gland complex was slightly, but not significantly higher than in acutely thyroparathyroidectomized cats.

Effect of Small Increments in Plasma Calcium Concentration on the Responsiveness of Forearm Resistance Vessels to Verapamil in Normal Subjects

1984 ◽  
Vol 67 (6) ◽  
pp. 613-618 ◽  
Author(s):  
B. F. Robinson ◽  
R. J. W. Phillips
Keyword(s):  
Calcium Concentration ◽  
Venous Blood ◽  
Normal Subjects ◽  
Plasma Calcium ◽  
Calcium Handling ◽  
Membrane Function ◽  
Resistance Vessels ◽  
Initial Control ◽  
Plasma Calcium Concentration ◽  
Small Increments

1. The effect of a small increase in local plasma calcium concentration on the responsiveness of the forearm resistance vessels to verapamil has been examined in normal subjects, by using a plethysmographic method with infusion of calcium and other agents into the brachial artery. 2. Infusion of calcium at a rate which increased the concentration in forearm venous blood by about 0.5 mmol/l caused basal blood flow to fall by 19% and the dilator response to verapamil to fall by 35% (n = 8; P<0.02). 3. When, after 46 min, the infusion of calcium was discontinued, the dilator response to verapamil increased to reach a level 53% higher than the initial control (n = 8; P<0.02). 4. Infusion of calcium had no effect on the dilator response to sodium nitroprusside. 5. Infusion of noradrenaline at a rate which caused a greater reduction in basal flow than that induced by calcium had no effect on the response to verapamil. 6. It is concluded that the dilator response to verapamil, which is thought to reflect activity of the potential operated system for calcium entry, is selectively depressed by a small elevation of plasma calcium concentration, but subsequently becomes elevated. These findings point to an important role for calcium in the regulation of membrane function in the resistance vessels and support the view that altered calcium handling may contribute to the development of primary hypertension.

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