Renal excretion of phosphate and calcium in parathyroidectomized starlings

1977 ◽  
Vol 233 (2) ◽  
pp. F138-F144 ◽  
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.

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

1976 ◽  
Vol 231 (4) ◽  
pp. 1152-1158 ◽  
Author(s):  
NB Clark ◽  
EJ Braun ◽  
Wideman RF
Keyword(s):  
Glomerular Filtration Rate ◽  
Parathyroid Hormone ◽  
Filtration Rate ◽  
Renal Excretion ◽  
Sturnus Vulgaris ◽  
Renal Handling ◽  
Calcium Clearance ◽  
Tubular Transport ◽  
Parathyroid Extract ◽  
Sodium And Potassium

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.

Renal excretion of nitrofurantoin (Furadantin)

1959 ◽  
Vol 197 (3) ◽  
pp. 580-584 ◽  
Author(s):  
Mary F. Paul ◽  
Raymond C. Bender ◽  
Esther G. Nohle
Keyword(s):  
Plasma Level ◽  
Intravenous Administration ◽  
Plasma Levels ◽  
Renal Excretion ◽  
Plasma Concentrations ◽  
Tubular Secretion ◽  
Tubular Reabsorption ◽  
Urine Flow ◽  
Curvilinear Relationship ◽  
Per Oral

Renal clearance of nitrofurantoin at various plasma levels was determined in the white rat. The clearance ratios (nitrofurantoin/inulin) exhibited a curvilinear relationship with the plasma level of the drug. The excretion of nitrofurantoin was found to be dependent upon the three following factors: glomerular filtration, tubular secretion and tubular reabsorption. The clearance of nitrofurantoin was not affected by urine flow nor by concurrent PAH administration. It was increased by acetazolamide and decreased slightly by probenecid. Thirty to forty per cent of the dose was recovered in the urine of rats or dogs after either per oral or intravenous administration. Rapid distribution of the drug was indicated by low plasma concentrations following intravenous administration.

Interrelations of arsenate and phosphate transport in the dog kidney

1963 ◽  
Vol 205 (4) ◽  
pp. 707-714 ◽  
Author(s):  
J. M. Ginsburg ◽  
W. D. Lotspeich
Keyword(s):  
Phosphate Transport ◽  
Tubular Secretion ◽  
Tubular Reabsorption ◽  
Urine Flow ◽  
Phosphate Concentration ◽  
Plasma Phosphate ◽  
Osmotic Diuresis ◽  
Competitive Mechanism ◽  
Dog Kidney

The relation between arsenate and phosphate transport in the dog kidney was studied by measuring the renal clearance of arsenate labeled with its radioactive isotope As74. The experiments were performed during osmotic diuresis induced by mannitol. The results demonstrate certain similarities in the transport of these ions. Arsenate undergoes a net tubular reabsorption which is inhibited as the plasma phosphate concentration is raised. The inverse relationship between arsenate transport and the plasma As:P ratio suggests a competitive mechanism for the interaction between the two ions Like phosphate, arsenate transport is inhibited by glucose and this effect is reversed by phlorizin. An important difference between arsenate and phosphate transport is the sensitivity of arsenate transport to urine flow. In vivo reduction of arsenate to arsenite and a net tubular secretion of arsenite has been observed. The results are discussed in terms of the known ability of arsenate to substitute for phosphate in biochemical reactions.

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).

Renal Sodium- and Potassium-Activated Adenosine Triphosphatase Deficiency During Post-obstructive Diuresis in the Rat

1974 ◽  
Vol 52 (1) ◽  
pp. 105-113 ◽  
Author(s):  
D. R. Wilson ◽  
W. Knox ◽  
E. Hall ◽  
A. K. Sen
Keyword(s):  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Filtration Rate ◽  
Renal Cortex ◽  
Urine Osmolality ◽  
Tubular Reabsorption ◽  
Enzyme Analysis ◽  
Outer Medulla ◽  
Sodium Load ◽  
Sodium And Potassium

Renal function studies and tissue enzyme analysis were carried out in rats with bilateral ureteral ligation (24 h) and after relief of obstruction at intervals of 2 h, 24 h, 3 days, and 7 days. A persistent decrease in glomerular filtration rate and in tubular reabsorption of sodium, solute, and water was noted at each interval after relief of obstruction. Renal sodium- and potassium-activated adenosine triphosphatase (Na–K-ATPase) activity was unchanged in kidneys obstructed for 24 h, but enzyme activity was decreased in the outer medulla of the kidney and, less often, in the renal cortex, at each interval studied during the post-obstructive period. Magnesium-dependent adenosine triphosphatase (Mg-ATPase) activity was not changed in any of the groups. In the post-obstructive kidney (24 h, 3 days, and 7 days) there was a significant correlation between the decrease in outer medullary Na–K-ATPase activity and the changes in filtered sodium load, tubular reabsorption of sodium, and urine osmolality. A deficiency of renal Na–K-ATPase could be important in the pathogenesis of post-obstructive natriuresis and diuresis.

Renal Excretion of l-Epinephrine in the Dog

1958 ◽  
Vol 193 (2) ◽  
pp. 371-374 ◽  
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.

Effect of sodium lactate on urate clearance in the Dalmatian and in the mongrel

1964 ◽  
Vol 207 (1) ◽  
pp. 113-117 ◽  
Author(s):  
Gabrielle H. Reem ◽  
Parker Vanamee
Keyword(s):  
Filtration Rate ◽  
Inhibitory Effect ◽  
Sodium Lactate ◽  
Tubular Secretion ◽  
Urine Flow ◽  
Osmotic Diuresis ◽  
Significant Drop ◽  
Urate Reabsorption

Sodium lactate was infused and urate clearance was measured under conditions of osmotic diuresis alone, as well as during simultaneous urate infusion. Urate clearance in the Dalmatian was not depressed by the administration of sodium lactate of 1.2–9.3 mEq/kg dl-sodium lactate, indicating that sodium lactate has no inhibitory effect on tubular secretion of urate. dl-Sodium lactate, 0.54–11.8 mEq/kg, was administered to four mongrel dogs in five experiments. In three experiments a significant drop of urate clearance in relation to filtration rate was observed. In two experiments in which urine flows exceeded 10 ml/min no significant decrease in urate clearance was recorded following dl-sodium lactate administration. The depression of urate clearance in the mongrel under conditions of moderate urine flow where reabsorption of solutes is more easily accomplished, and the absence of this effect in the Dalmatian as well as in the mongrel under conditions of vigorous diuresis where reabsorption of solutes is greatly diminished, lends support to the belief that sodium lactate depresses urate clearance by facilitating urate reabsorption in the mongrel.

The renal response of sheep to feeding

1964 ◽  
Vol 15 (2) ◽  
pp. 289 ◽  
Author(s):  
BD Stacy ◽  
AH Brook
Keyword(s):  
Renal Excretion ◽  
Extracellular Fluid ◽  
Urine Flow ◽  
Hydrogen Ion ◽  
Urine Ph ◽  
Renal Response ◽  
Alkaline Urine ◽  
Renal Clearances ◽  
Acute Changes ◽  
Sodium And Potassium

Acute changes in renal excretion occurred when pen-fed sheep were given their daily feed. There was a reduction in the rate of urine flow and the concentration of the urine increased. During the oliguric phase, sodium and potassium excretion decreased whereas hydrogen ion excretion increased and caused acidification (pH 5–6) of the normally alkaline urine (pH 7–8). Renal clearances of inulin and PAH did not indicate that the urinary changes were due to altered renal haemodynamics. It is suggested that the observed renal response was a reflection of the sudden shift of extracellular fluid into the gut at the onset of feeding.

scholarly journals The role of tubular reabsorption in the renal excretion of bile acids

1977 ◽  
Vol 166 (1) ◽  
pp. 65-73 ◽  
Author(s):  
S Barnes ◽  
J L Gollan ◽  
B H Billing
Keyword(s):  
Bile Acids ◽  
Renal Excretion ◽  
Rat Kidney ◽  
Tubular Secretion ◽  
Tubular Reabsorption ◽  
Free Medium ◽  
Proximal Tubular ◽  
Protein Free Medium ◽  
Conjugated Bilirubin

1. The renal excretion of bile acids was studied in an isolated rat kidney preparation perfused with a protein-free medium. 2. Tubular reabsorption exceeded 95% for both non-sulphated and sulphated bile acids at filtered loads of less than 30 nmol/min. 3. At low filtered loads the reabsorption of taurocholate and taurochenodeoxycholate was almost complete. Efficient reabsorption of taurochenodeoxycholate was maintained over a wider range of filtered loads than for taurocholate. These observations suggest that active transport may occur. 4. At high filtered loads saturation of reabsorption of taurocholate and taurochenodeoxycholate did not occur, which indicates that passive diffusion is involved in reabsorption. 5. Active proximal-tubular secretion of bile acids was not demonstrated in competition experiments with p-aminohippurate. 6. The fractional reabsorption of taurocholate, chenodeoxycholate 3,7-disulphate and chenodeoxycholate 7-monosulphate was decreased by the addition of taurochenodeoxycholate to the perfusate, so that their renal excretion was enhanced. This interaction between the bile acids for reabsorption may explain the different composition of bile acids in urine compared with that in plasma in cholestasis in man. 7. Conjugated bilirubin decreased the fractional reabsorption of both taurocholate and taurochenodeoxycholate at low filtered loads (less than 30 nmol/min) but not at high filtered loads (400 nmol/min).

Renal Excretion of Radioiodide in Rats

1958 ◽  
Vol 193 (2) ◽  
pp. 379-385 ◽  
Author(s):  
N. S. Halmi ◽  
L. T. King ◽  
R. R. Widner ◽  
A. C. Hass ◽  
R. G. Stuelke
Keyword(s):  
Transport Mechanism ◽  
Renal Excretion ◽  
Competitive Inhibition ◽  
Sodium Thiosulfate ◽  
Tubular Reabsorption ◽  
Urine Flow ◽  
Male Rats ◽  
Renal Tubules ◽  
Sodium Salts ◽  
Active Transport Mechanism

Elimination of radioiodide by the kidney of adult male rats pretreated with a single dose of propylthiouracil was measured. Rats given water or isotonic saccharose served as controls. Renal clearance of radioiodide (CI131) was greatly enhanced (up to 100-fold) by the sodium salts of chloride, perchlorate, stable iodide, bromide and bicarbonate, and by choline iodide, but not by sodium thiosulfate. Under most conditions CI131 markedly exceeded the CCl and CNa of the same animals, which suggest that renal tubules are less permeable to iodide than to chloride or sodium. CI131/CNa varied greatly, its magnitude being dependent on the loading solution used. CI131 showed no correlation with urine flow or excretion of endogenous creatinine-like chromogen (UCrV) when groups receiving different treatments were compared. Both urine flow and UCrV showed only minor variations among these groups. Our findings are most easily explained by the hypothesis that tubular reabsorption of iodide filtered by the glomeruli involves, possibly in addition to a passive process, an active transport mechanism capable of saturation by iodide and (competitive?) inhibition by other anions.

Sign in / Sign up

Export Citation Format

Share Document