Glomerular filtration rate in weaned elephant seal pups during natural, long term fasts

1989 ◽  
Vol 67 (7) ◽  
pp. 1752-1756 ◽  
Author(s):  
S. D. Pernia ◽  
D. P. Costa ◽  
C. Leo Ortiz
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Water Conservation ◽  
Urine Output ◽  
Filtration Rate ◽  
Extracellular Volume ◽  
Absolute Magnitude ◽  
Elephant Seal ◽  
Tubular Reabsorption ◽  
The Difference

Low urine output (< 200 mL/day) seen in weaned elephant seal pups is consistent with the physiological necessity of strict water conservation during periods of protracted, natural fasts. However, urine output represents only the difference between glomerular filtration rate (GFR) and tubular reabsorption and thus provides no information about the absolute magnitude of these parameters or their role in homeostatic regulation during the fast. We measured GFR, and extracellular volume (ECV) and estimated tubular reabsorption in seven pups that had been fasting > 6 weeks and in three others that had begun to feed in captivity using standard [3H]inulin and [125I]iothalamate clearance techniques. In fasting pups, GFR and ECV ranged from 78.9 to 135.2 mL/min and from 6.3 to 15.4 L, respectively. The GFR values are 59–91% [Formula: see text] of that predicted by standard body mass allometry. These data suggest that (i) low urine output is a consequence of tubular reabsorption rather than depressed GFR; (ii) a small but significant N and electrolyte load resulting from oxidation and reorganization of body tissue during development requires near "normal" renal function despite the potential loss of water from excess urine formation.

scholarly journals Influence of Early Bladder Imaging in Experimental Rabbits on the Quantitative Determination of Glomerular Filtration Rate by the Gates Method

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Changyin Wang ◽  
Shun Li ◽  
Chun Gao ◽  
Wasili Maimaiti ◽  
Qisheng Yang ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Load Test ◽  
Renal Uptake ◽  
Quantitative Calculation ◽  
Uptake Rates ◽  
Before And After ◽  
Baseline Status ◽  
The Difference

Objective. To investigate the influence of early bladder imaging (EBI) in experimental rabbits on the quantitative calculation of glomerular filtration rate (GFR) by the Gates method. Methods. We retrospectively analyzed the data of dynamic renal scintigraphy (DRS) in experimental rabbits. We calculated renal uptake during minutes 1-2 and 2-3 by correcting bladder radioactivity and computed the split GFR by renal uptake. Then, the EBI and GFR between 1-2 min and 2-3 min were compared, respectively. Results. The EBI proportion (57.3%) at 2-3 min of DRS was higher than that (8.5%) at 1-2 min ( P < 0.05 ). The correlations between the 1-2 min and 2-3 min uptake rates of unobstructed kidneys after correction ( r = 0.952 ‐ 0.979 ) were higher than those before correction ( r = 0.859 ‐ 0.936 ). However, the correlation between the two in obstructed kidneys was not improved ( r before = 0.967 versus r after = 0.968 ). For unobstructed kidneys, the difference in GFR based on 2-3 min uptake between before and after correction was significant ( P < 0.05 ), but not in obstructed kidneys ( P > 0.05 ). For GFR based on 1-2 min uptake, the difference between before and after correction was not significant in obstructed or unobstructed kidneys ( P > 0.05 ). Before correction, the GFR of unobstructed kidneys of 10.5% of the rabbits in the protein load test was lower than that in the baseline status, but not so after correction. Conclusion. The 2-3 min EBI on DRS has a significant influence on the GFR calculated by the Gates method in experimental rabbits. Controlling water intake or calculating the GFR by 1-2 min renal uptake helps to avoid the influence of EBI on GFR.

scholarly journals Glomerular Filtration Rate as a Predictor of Outcome in Acute Coronary Syndrome Complicated by Atrial Fibrillation

2020 ◽  
Vol 9 (5) ◽  
pp. 1466
Author(s):  
Domenico Santoro ◽  
Guido Gembillo ◽  
Giuseppe Andò
Keyword(s):  
Atrial Fibrillation ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Cardiovascular Health ◽  
Coronary Syndrome ◽  
Close Relationship ◽  
The Difference ◽  
New Onset

The close relationship between kidney and heart is well known. Cardiovascular impairment contributes to the worsening of renal function and kidney failure worsens cardiovascular health. Atrial fibrillation (AF) is a frequent issue in patients with Chronic Kidney Disease (CKD) and several studies have demonstrated that AF impacts negatively on their quality of life and outcomes. Understanding the mechanisms leading to the progression of CKD, new-onset AF and acute myocardial infarction (AMI) is a key issue. The evaluation of Glomerular Filtration Rate (GFR) could make the difference in this equilibrium and suggests specific strategies in the treatment of the population at major risk of cardiovascular events. This intriguing connection paves the way for necessary further investigations.

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).

scholarly journals Extracellular Volume and Glomerular Filtration Rate in Children with Chronic Kidney Disease

2011 ◽  
Vol 6 (4) ◽  
pp. 741-747 ◽  
Author(s):  
Alison G. Abraham ◽  
Alvaro Muñoz ◽  
Susan L. Furth ◽  
Bradley Warady ◽  
George J. Schwartz
Keyword(s):  
Chronic Kidney Disease ◽  
Glomerular Filtration Rate ◽  
Kidney Disease ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Extracellular Volume

MAXIMUM TUBULAR REABSORPTION CAPACITY OF GLUCOSE IN DIABETES MELLITUS

1965 ◽  
Vol 50 (1) ◽  
pp. 79-94 ◽  
Author(s):  
A. Vitelli ◽  
C. Cattaneo ◽  
P. F. Martini
Keyword(s):  
Diabetes Mellitus ◽  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Vascular Disease ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Normal Subjects ◽  
Tubular Reabsorption ◽  
Functional Changes ◽  
Two Factors

ABSTRACT The glomerular filtration rate (GFR) and maximum tubular reabsorption of glucose (TmG) were measured in 24 cases of diabetes mellitus. The patients, who were of different ages, varied with regard to the severity and duration of the disease and 11 patients showed clinical and functional evidence of vascular disease. The GFR and TmG were diminished in almost 50 per cent of cases, and the diminution of the two factors was closely correlated. The incidence of these renal functional changes was almost the same in the group of diabetics with vascular disease as in the group without complications. The GFR and TmG were not correlated with the age of the patients or with the severity of diabetes, though these factors were to some extent correlated with the duration of the disease. No relationship was observed between the incidence of impairment of the renal function and sex. The examinations carried out in this series of cases as well as in a number of normal subjects suggest various considerations with regard to the value of the various techniques which have been proposed for the measurement of the TmG.

Vasopressin contamination as a cause of some apparent renal actions of prolactin

1976 ◽  
Vol 54 (6) ◽  
pp. 887-890 ◽  
Author(s):  
R. Keeler ◽  
N. Wilson
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Urine Output ◽  
Filtration Rate ◽  
Urine Osmolality ◽  
Brattleboro Rats ◽  
Urine Excretion ◽  
Renal Effects ◽  
Antidiuretic Activity ◽  
Electrolyte Retention

The injection or infusion of NIAMDD prolactin (NIH P-S-10) into unanesthetized rats resulted in water and electrolyte retention with a large increase in urine osmolality but no effect on glomerular filtration rate. Since these effects on urine output were also observed in homozygous Brattleboro rats, the antidiuretic activity could not have been caused by the release of endogenous antidiuretic hormone.Radioimmunoassay of NIH prolactin showed that it was contaminated with vasopressin (20 ng/mg of prolactin). By comparison, Sigma prolactin had no observed effect on urine excretion and contained very little vasopressin (2.5 ng/mg).It is concluded that some of the renal effects of prolactin that have been reported in the literature may have been caused by the contaminating vasopressin.

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