Parathyroid hormone and renal excretion of phosphate and calcium in normal starlings

The renal handling of calcium, phosphate, sodium, and potassium was studied in normal and parathyroid extract (PTE)-injected starlings, Sturnus vulgaris. The birds were anesthetized with Equi-Thesin and infused intravenously with 2.5% mannitol containing [14C]inulin. Normal starlings actively reabsorb all four of these substances. After intravenous administration of 50 IU PTE/100 g body wt, the relative phosphate clearance (CPO4/CIn) as well as tubular transfer of phosphate (TPO4) increased significantly. Phosphate secretion occurred and usually persisted longer than 2 h. The relative calcium clearance also rose after PTE, but the TCa did not shift. This probably indicates that the tubular transport maximum (Tm) for calcium had been exceeded. The relative clearances of sodium and potassium also increased after PTE; however, only the rise in CNa/CIn was significantly different from the controls. The glomerular filtration rate (CIn) also increased significantly after PTE, but this effect was transient and cannot explain the longer lasting effects of PTE on excretion of phosphate, calcium, or sodium.

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Renal excretion of phosphate and calcium in parathyroidectomized starlings

AJP Renal Physiology ◽

10.1152/ajprenal.1977.233.2.f138 ◽

1977 ◽

Vol 233 (2) ◽

pp. F138-F144 ◽

Cited By ~ 2

Author(s):

N. B. Clark ◽

R. F. Wideman

Keyword(s):

Filtration Rate ◽

Renal Excretion ◽

Tubular Secretion ◽

Tubular Reabsorption ◽

Urine Flow ◽

Phosphate Homeostasis ◽

Calcium Clearance ◽

Parathyroid Extract ◽

Potassium Secretion ◽

Sodium And Potassium

Renal excretion patterns of calcium, phosphate, sodium, and potassium were studied in parathyroidectomized (PTX) and parathyroid extract (PTE)-injected PTX starlings. Sturnus vulgaris. Anesthetized birds (Equi-Thesin or Dial) were infused intravenously with 2.5% mannitol containing [14C]inulin. PTX caused significant hypocalcemia, hyperphosphatemia, increased relative calcium clearance (CCa/CIn), and decreased relative clearances of phosphate and potassium, but did not change the clearance of sodium. Glomerular filtration rate (GFR=CIn) and urine flow remained unchanged up to 2 h after PTX. PTE administration 3 h after PTX returned serum calcium and phosphate values to control levels and caused a transient (10-min) increase in GFR. Following PTE, the relative clearances of phosphate, sodium- and potassium increased, while that of calcium decreased significantly relative to the PTX levels. PTE caused net tubular secretion of phosphate, decreased tubular reabsorption of sodium and potassium (sometimes potassium secretion), and a return of excretion of calcium to control levels. These studies indicate that the parathyroid role in calcium and phosphate homeostasis in starlings is predominantly on the kidney.

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

AJP Renal Physiology ◽

10.1152/ajprenal.1987.253.1.f34 ◽

1987 ◽

Vol 253 (1) ◽

pp. F34-F40 ◽

Cited By ~ 1

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.

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Renal Excretion of l-Epinephrine in the Dog

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1958.193.2.371 ◽

1958 ◽

Vol 193 (2) ◽

pp. 371-374 ◽

Cited By ~ 5

Author(s):

Richard T. Jones ◽

William D. Blake

Keyword(s):

Glomerular Filtration Rate ◽

Glomerular Filtration ◽

Plasma Flow ◽

Filtration Rate ◽

Renal Excretion ◽

Renal Plasma Flow ◽

Blocking Agent ◽

Tubular Secretion ◽

Sodium Pentobarbital ◽

Tubular Transport

The renal excretion of epinephrine was studied in dogs anesthetized with sodium pentobarbital. Epinephrine in plasma and urine was quantitatively estimated by the fluorometric method of Lund. Glomerular filtration rate (creatinine clearance), renal plasma flow (PAH clearance) and PAH transport were employed as parameters of renal function. During periods of intravenous infusion of epinephrine, the percentage of hormone excreted was about 4.6% of that infused. The renal clearance of epinephrine was significantly greater than the glomerular filtration rate though less than renal plasma flow. From this and other information it was concluded that epinephrine is excreted both by tubular transport (tubular secretion) and glomerular filtration. The tubular transport of epinephrine was not inhibited by either 2,4-dinitrophenol or an adrenergic blocking agent.

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Excretion of progastrin products in human urine

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1999.276.4.g985 ◽

1999 ◽

Vol 276 (4) ◽

pp. G985-G992 ◽

Cited By ~ 2

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.

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

Toxins ◽

10.3390/toxins11110635 ◽

2019 ◽

Vol 11 (11) ◽

pp. 635 ◽

Cited By ~ 6

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.

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Renal excretion of chromium-51 chloride in the dog

AJP Renal Physiology ◽

10.1152/ajprenal.1984.246.6.f870 ◽

1984 ◽

Vol 246 (6) ◽

pp. F870-F878 ◽

Cited By ~ 3

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.

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Serum NGAL, BNP, PTH, and albumin do not improve glomerular filtration rate estimating formulas in children

European Journal of Pediatrics ◽

10.1007/s00431-021-04019-w ◽

2021 ◽

Author(s):

Julie Mouron-Hryciuk ◽

François Cachat ◽

Paloma Parvex ◽

Thomas Perneger ◽

Hassib Chehade

Keyword(s):

Glomerular Filtration Rate ◽

Parathyroid Hormone ◽

Serum Creatinine ◽

Brain Natriuretic Peptide ◽

Glomerular Filtration ◽

Natriuretic Peptide ◽

Cystatin C ◽

Filtration Rate ◽

Neutrophil Gelatinase Associated Lipocalin ◽

Neutrophil Gelatinase

AbstractGlomerular filtration rate (GFR) is difficult to measure, and estimating formulas are notorious for lacking precision. This study aims to assess if the inclusion of additional biomarkers improves the performance of eGFR formulas. A hundred and sixteen children with renal diseases were enrolled. Data for age, weight, height, inulin clearance (iGFR), serum creatinine, cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), parathyroid hormone (PTH), albumin, and brain natriuretic peptide (BNP) were collected. These variables were added to the revised and combined (serum creatinine and cystatin C) Schwartz formulas, and the quadratic and combined quadratic formulas. We calculated the adjusted r-square (r2) in relation to iGFR and tested the improvement in variance explained by means of the likelihood ratio test. The combined Schwartz and the combined quadratic formulas yielded best results with an r2 of 0.676 and 0.730, respectively. The addition of BNP and PTH to the combined Schwartz and quadratic formulas improved the variance slightly. NGAL and albumin failed to improve the prediction of GFR further. These study results also confirm that the addition of cystatin C improves the performance of estimating GFR formulas, in particular the Schwartz formula.Conclusion: The addition of serum NGAL, BNP, PTH, and albumin to the combined Schwartz and quadratic formulas for estimating GFR did not improve GFR prediction in our population. What is Known:• Estimating glomerular filtration rate (GFR) formulas include serum creatinine and/or cystatin C but lack precision when compared to measured GFR.• The serum concentrations of some biological parameters such as neutrophil gelatinase-associated lipocalin (NGAL), parathyroid hormone (PTH), albumin, and brain natriuretic peptide (BNP) vary with the level of renal function. What is New:• The addition of BNP and PTH to the combined quadratic formula improved its performance only slightly. NGAL and albumin failed to improve the prediction of GFR further.

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USE OF HEMODIALYSIS IN THE TREATMENT OF QUINIDINE POISONING

PEDIATRICS ◽

10.1542/peds.52.1.95 ◽

1973 ◽

Vol 52 (1) ◽

pp. 95-99

Author(s):

Ekkehard W. Reimold ◽

Walter J. Reynolds ◽

David E. Fixler ◽

LaVerne McElroy

Keyword(s):

Blood Flow ◽

Glomerular Filtration Rate ◽

Glomerular Filtration ◽

Treatment Period ◽

Filtration Rate ◽

Renal Excretion ◽

Artificial Kidney ◽

Flow Rates ◽

Urine Acidification ◽

Forced Diuresis

Hemodialysis was used in addition to forced diuresis in the treatment of quinidine poisoning of a 3-year-old girl. The estimated retained dose of quinidine was 1,600 mg. During a 36-hour treatment period the patient excreted through the kidneys 768.1 mg quinidine (21.3 mg/hr). Hemodialysis almost doubled the quinidine elimination by removing 145 mg in eight hours (18.1 mg/hr): renal excretion, 55%; hemodialysis, 45%. The quinidine elimination with dialysis is high when high blood flow rates through the artificial kidney can be maintained. Adequate glomerular filtration rate and urine acidification are necessary for high renal excretion of quinidine.

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