scholarly journals TUBULAR SECRETION OF CREATINE, TRIMETHYLAMINE OXIDE, AND OTHER ORGANIC BASES BY THE AGLOMERULAR KIDNEY OF LOPHIUS AMERICANUS

1958 ◽  
Vol 42 (2) ◽  
pp. 319-327 ◽  
Author(s):  
Roy P. Forster ◽  
Fredrik Berglund ◽  
Barbara R. Rennick
Keyword(s):  
Plasma Concentration ◽  
Tubular Secretion ◽  
Tubular Reabsorption ◽  
Cyanine Dye ◽  
Transport Mechanisms ◽  
Organic Base ◽  
Organic Bases ◽  
Trimethylamine Oxide ◽  
Tetraethylammonium Ion ◽  
Concentration Ratios

Creatine and trimethylamine oxide (TMAO) are the chief nitrogenous constituents of normal Lophius urine, and both of these organic bases characteristically have high urine/plasma concentration ratios. Competition studies involving various organic bases indicate that creatine and TMAO are excreted independently by separate transport mechanisms. TMAO excretion is inhibited competitively by tetraethylammonium ion (TEA) and by cyanine dye No. 863—compounds previously shown to be transferred actively by an organic base-secreting mechanism of general occurrence among vertebrates. TEA does not inhibit competitively the active tubular reabsorption of TMAO in Squalus with doses which markedly depress its tubular excretion in Lophius. Glycine, which inhibits creatine reabsorption in the dog, does not interfere competitively with its secretion in Lophius.

Renal excretion of radiofluoride in the dog

1960 ◽  
Vol 198 (4) ◽  
pp. 829-832 ◽  
Author(s):  
Curtis H. Carlson ◽  
W. D. Armstrong ◽  
Leon Singer ◽  
Lerner B. Hinshaw
Keyword(s):  
Plasma Concentration ◽  
Glomerular Filtration ◽  
Renal Excretion ◽  
Urine Volume ◽  
Urine Concentration ◽  
Tubular Reabsorption ◽  
Carrier Free ◽  
Renal Clearances ◽  
Concentration Ratios

Renal clearances of continuously infused radiofluoride were measured in 10 dogs in which a large part of the skeleton had been excluded from the system in order to produce a more constant plasma radiofluoride concentration. The results were evaluated to describe the factors of glomerular filtration and tubular reabsorption of fluoride under several conditions. The animals that received carrier-free radiofluoride infusions excreted urine with a mean radiofluoride concentration 3.4–14.5 times that of the plasma. The urine-to-plasma concentration ratios obtained with animals given a load of stable fluoride was 13.5–29.6. An increased urine volume resulted in a decreased tubular reabsorption of fluoride and the clearance was increased. Chlorothiazide increased radiofluoride excretion but decreased the urine concentration. The radiofluoride clearances were always less than the creatinine clearances but were 7.8–179 times the chloride clearances. The effect of chlorothiazide was to decrease the ratio of fluoride to chloride clearance by increasing chloride clearance more than fluoride clearance.

Effect of trimethylamine and its homologues on renal conservation of trimethylamine oxide by the spiny dogfish, Squalus acanthias

1958 ◽  
Vol 196 (1) ◽  
pp. 93-99 ◽  
Author(s):  
Julius J. Cohen ◽  
Marcus A. Krupp ◽  
Charles A. Chidsey ◽  
Charles I. Biltz
Keyword(s):  
Specific Effect ◽  
Tubular Secretion ◽  
Tubular Reabsorption ◽  
Urine Flow ◽  
Squalus Acanthias ◽  
Weak Base ◽  
Physiological Regulation ◽  
Trimethylamine Oxide ◽  
Renal Tubular Reabsorption ◽  
Renal Tubular

In renal clearance experiments with dogfish, trimethylamine HCL (TMA) administration (i.m.) results in a large increase in trimethylamine oxide (Oxide) excretion. This is shown to occur by inhibition of net renal tubular reabsorption of the Oxide. The TMA, on the other hand, reaches the urine by net tubular secretion in quantities which are consistent with the attainment of diffusion equilibrium across the pH gradient between urine and plasma. The effect of TMA is not related to increased urine flow but is a specific effect on Oxide reabsorption. The administration of the homologue of TMA, dimethylamine, results in a similar but less profound blockade of Oxide reabsorption. Methylamine, however, has no effect at all on Oxide reabsorption. Large excretory losses of TMAO occurred without any change in TMAO plasma level, further indicating the physiological regulation of the plasma concentration of this weak base.

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.

Synthesis of Sterically Congested Carbamates of Carbohydrates through Organic Base Catalysis

Synthesis ◽  
2019 ◽  
Vol 51 (15) ◽  
pp. 2897-2908 ◽  
Author(s):  
Anji Chen ◽  
Dan Wang ◽  
Lalith P. Samankumara ◽  
Guijun Wang
Keyword(s):  
Hydroxy Group ◽  
Current Method ◽  
Building Blocks ◽  
Base Catalysis ◽  
Organic Base ◽  
Molecular Assemblies ◽  
Effective Catalyst ◽  
Organic Bases ◽  
Derivatives Of ◽  
General Method

4,6-O-Benzylidene acetal protected α-methoxy d-glucose and d-glucosamine are useful building blocks for the syntheses of carbohydrate derivatives and functional molecular assemblies. In this research, we have developed a general method for the preparation of C-3 carbamate derivatives of densely functionalized glucose and glucosamine with isocyanates using organic bases as catalysts. Without a suitable catalyst, the C-3 hydroxy group of the glucosamine derivative could not be converted into the corresponding carbamates when treated with isocyanates. Several organic bases were screened as the catalysts for the reactions, and we discovered that 5.0 mol% of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was an effective catalyst for the carbamoylation reaction. A library of both alkyl and aryl carbamate derivatives of the two sterically congested carbohydrates have been effectively synthesized using the current method.

A COMPARISON BETWEEN THE UPTAKES OF RADIOACTIVE PERCHLORATE AND IODIDE BY RAT AND GUINEA-PIG THYROID GLANDS

1969 ◽  
Vol 45 (1) ◽  
pp. 1-8 ◽  
Author(s):  
S. Y. CHOW ◽  
L. R. CHANG ◽  
M. S. YEN
Keyword(s):  
Plasma Concentration ◽  
Marked Effect ◽  
Specific Activity ◽  
Chronic Administration ◽  
Anion Transport ◽  
Thyroid Stimulating Hormone ◽  
Thyroid Glands ◽  
Stable Anion ◽  
Dose Levels ◽  
Concentration Ratios

SUMMARY Previous studies indicated that 36Cl-labelled perchlorate is concentrated by rat and rabbit thyroid gland. However, the extent of concentration of radioactive perchlorate in the gland was much less than that of iodide. Since perchlorate itself has a marked effect on anion transport in the thyroid and the specific activity of available [36C]perchlorate is very low, the stable anion as a carrier present in the injected radioactive perchlorate solution may affect the uptake of this radioactive compound by the gland. In this study, radioactive solutions of perchlorate and iodide containing different amounts of stable perchlorate or iodide (dosages ranged from 0·005 to 5 m-equiv./kg. body weight) were injected into groups of rats and guineapigs, and the thyroid: plasma concentration ratios of radioactive perchlorate and iodide were calculated and compared. These experiments were also repeated in animals pretreated with thyroid-stimulating hormone (TSH), after chronic administration of propylthiouracil (PTU), as well as in hypophysectomized animals. At the same dose levels of perchlorate, there was no difference in thyroid: plasma concentration ratios of radioactive perchlorate and iodide in control rats and guinea-pigs or in treated ones.

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).

Prediction of milk/plasma concentration ratios of drugs and environmental pollutants

2009 ◽  
Vol 44 (6) ◽  
pp. 2452-2458 ◽  
Author(s):  
Michael H. Abraham ◽  
Javier Gil-Lostes ◽  
Mohammad Fatemi
Keyword(s):  
Plasma Concentration ◽  
Environmental Pollutants ◽  
Concentration Ratios
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