Effect on kidney S35O4 uptake of compounds related to SO4 transport and metabolism

Experiments have been carried out to test the effects on S35O4 accumulation by rat kidney cortex slices in vitro of 1) compounds known to affect renal SO4 reabsorption (thiosulfate, amino acids); 2) compounds secreted by the kidney, or known to affect specific cellular transport systems (including tetraethylammonium ions, guanidine, creatinine, carinamide, probenecid, phloretin, diethylstilbestrol, ethylenediaminetetraacetate sodium); and 3) compounds related to SO4 metabolism (aryl sulfatase substrates). Under the conditions of the experiment, net S35O4 uptake was depressed by thiosulfate, certain amino acids, carinamide, phloretin, diethylstilbestrol, and aryl sulfatase substrates. It was enhanced by ethylenediaminetetraacetate sodium. Other compounds were without effect. These results are discussed from the point of view of the possible relationship between SO4 accumulation in vitro and transport in vivo.

Download Full-text

Inhibition of cellular transport processes by 5-thio-d-glucopyranose

Biochemical Journal ◽

10.1042/bj1300919 ◽

1972 ◽

Vol 130 (4) ◽

pp. 919-925 ◽

Cited By ~ 59

Author(s):

Roy L. Whistler ◽

William C. Lake

Keyword(s):

Amino Acids ◽

Rat Kidney ◽

Transport Processes ◽

Diaphragm Muscle ◽

Rabbit Kidney ◽

Kidney Cortex ◽

Facilitated Diffusion ◽

Cellular Transport ◽

Rat Kidney Cortex ◽

Diffusion Transport

5-Thio-d-glucopyranose, the nearest analogue of normal d-glucose, which is proving a useful tool in examinations of d-glucose biochemistry, affects active and facilitated-diffusion transport processes. 5-Thio-d-glucose is readily transported in rabbit kidney-cortex slices and reaches a tissue/medium ratio of 6.5 within 40min. The sulphur analogue shows typical saturation kinetics with a Km value of 2.4mm and Vmax. value of 70μmol/h per g of cell water. Uptake of 5-thio-d-glucose is phlorrhizin-sensitive, Na+-dependent and energy-dependent. d-Galactose and methyl α-d-glucopyranoside transport is competitively inhibited by 5-thio-d-glucose with Ki values of 4.8 and 9.7mm respectively. 5-Thio-d-glucose thus shows all of the characteristics of active transport in kidney cortex. Transport of neutral amino acids in rat kidney cortex is inhibited by 5-thio-d-glucose. Thus 5.6mm-5-thio-d-glucose causes a 25–30% inhibition of the transport of glycine and the non-metabolized amino acids cycloleucine and α-aminoisobutyric acid. 5-Thio-d-glucose is freely taken up by the facilitated-diffusion transport system in rat diaphragm muscle. The sulphur analogue inhibits the transport of d-xylose in this tissue but has no effect on the uptake of d-arabinose. It is concluded that the ring heteroatom is not an effector of binding in the transport processes examined and causes no important alteration in the conformation of the sugar. The diabetogenic action produced by 5-thio-d-glucose is due, in part, to the ability of the analogue to interfere with cellular transport processes that use d-glucose.

Download Full-text

Separate Transport Systems for Sugars and Amino Acids in Developing Rat Kidney Cortex

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.68.2.372 ◽

1971 ◽

Vol 68 (2) ◽

pp. 372-376 ◽

Cited By ~ 14

Author(s):

S. Segal ◽

C. Rea ◽

I. Smith

Keyword(s):

Amino Acids ◽

Rat Kidney ◽

Transport Systems ◽

Kidney Cortex ◽

Rat Kidney Cortex ◽

Developing Rat

Download Full-text

Accumulation of Sulfate by Mitochondria of Rat Kidney Cortex

The Journal of General Physiology ◽

10.1085/jgp.45.4.757 ◽

1962 ◽

Vol 45 (4) ◽

pp. 757-775 ◽

Cited By ~ 14

Author(s):

Robert W. Winters ◽

Adelaide M. Delluva ◽

Ingrith J. Deyrup ◽

Robert E. Davies

Keyword(s):

Rat Kidney ◽

Kidney Cortex ◽

Ph Optimum ◽

Rat Kidney Cortex ◽

Sulfate Ions ◽

Straight Line ◽

Freundlich Adsorption Isotherm ◽

Ambient Concentrations

Twice washed mitochondria from rat kidney cortex can accumulate sulfate ions from low (10-7 M) ambient concentrations to create virtual gradients of several hundred to one. This sulfate is subsequently released. The activation energy for the uptake is 12,000 calories per mole; for release it is about 30,000 calories per mole. Variations in the sulfate concentration of the medium show that there is a straight line Freundlich adsorption isotherm over a million-fold range of concentration of sulfate in the medium. There are 9 x 104 sites at 10-5 M and 9 x 105 sites at 10-3 M sulfate per average single mitochondrion. Preincubation at 30°C rapidly destroys the ability to accumulate sulfate. Partial protection occurs if oxidative phosphorylation is proceeding during the preincubation. The concentration of the endogenous inorganic sulfate of twice washed mitochondria is 4.2 x 10-4 moles per liter of mitochondrial pellet water; 99.85 per cent of this endogenous sulfate is inexchangeable with external sulfate in vitro. It is all exchangeable in vivo. The pH optimum for accumulation of radiosulfate from dilute external sulfate concentrations is 5.5. These observations show that there is a delicate and specific mechanism in mitochondria from kidney cortex which accumulates sulfate. The chemical nature of the accumulated sulfate is unknown.

Download Full-text

3-Mercaptopicolinic acid, an inhibitor of gluconeogenesis

Biochemical Journal ◽

10.1042/bj1380387 ◽

1974 ◽

Vol 138 (3) ◽

pp. 387-394 ◽

Cited By ~ 121

Author(s):

N. W. DiTullio ◽

C. E. Berkoff ◽

B. Blank ◽

V. Kostos ◽

E. J. Stack ◽

...

Keyword(s):

Rat Kidney ◽

Diabetic Rats ◽

Kidney Cortex ◽

Hepatic Glycogen ◽

Hypoglycaemic Effect ◽

Rat Kidney Cortex ◽

Urea Production ◽

Rat Livers

1. 3-Mercaptopicolinic acid (SK&F 34288) inhibited gluconeogenesis in vitro, with lactate as substrate, in rat kidney-cortex and liver slices. 2. In perfused rat livers, gluconeogenesis was inhibited when lactate, pyruvate or alanine served as substrate, but not with fructose, suggesting pyruvate carboxylase or phosphoenolpyruvate carboxylase as the site of inhibition. No significant effects were evident in O2 consumption, hepatic glycogen, urea production, or [lactate]/[pyruvate] ratios. 3. A hypoglycaemic effect was evident in vivo in starved and alloxan-diabetic rats, starved guinea pigs and starved mice, but not in 4h-post-absorptive rats. 4. In the starved rat the hypoglycaemia was accompanied by an increase in blood lactate. 5. A trace dose of [14C]lactate in vivo was initially oxidized to a lesser extent in inhibitor-treated rats, but during 90min the total CO2 evolved was slightly greater. The total amount of the tracer oxidized was not significantly different from that in the controls.

Download Full-text

H+ gradient-driven dipeptide reabsorption in proximal tubule of rat kidney. Studies in vivo and in vitro

AJP Renal Physiology ◽

10.1152/ajprenal.1987.253.3.f448 ◽

1987 ◽

Vol 253 (3) ◽

pp. F448-F457 ◽

Cited By ~ 4

Author(s):

S. Silbernagl ◽

V. Ganapathy ◽

F. H. Leibach

Keyword(s):

Amino Acids ◽

Proximal Tubule ◽

Rat Kidney ◽

High Capacity ◽

Peptide Transport ◽

Transport Systems ◽

Negative Membrane Potential ◽

Uptake Process

Microinfusion of glycylsarcosine into superficial nephron sections showed that the dipeptide was reabsorbed mainly in late portions of the rat proximal tubule. In vivo microperfusion data demonstrated a saturable, high-capacity, low-affinity dipeptide reabsorption mechanism that was inhibited by other peptides but not by amino acids or peptidase inhibitors. The reabsorption was enhanced by lowering the luminal pH from 7.5 to 5.5. In vitro studies with rat cortical brush-border vesicles showed that glycylsarcosine uptake was independent of a Na+ gradient and greater uptake occurred when the extravesicular pH was acidic compared with the intravesicular pH. An inward-directed H+ gradient stimulated glycylsarcosine uptake and caused a transient accumulation of the dipeptide inside the vesicles above the equilibrium value. The presence of a proton ionophore abolished the H+ gradient-dependent uptake. An inside-negative membrane potential stimulated the initial uptake of the dipeptide. The uptake process was saturable and inhibited by other peptides but not by amino acids. The vesicle studies also showed that there are at least two peptide transport systems functioning in these vesicles, one a high-affinity, low-capacity type and the other a low-affinity, high-capacity type.

Download Full-text

Effect of metal ions on in vitro gluconeogenesis in rat kidney cortex slices

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1965.208.5.841 ◽

1965 ◽

Vol 208 (5) ◽

pp. 841-846 ◽

Cited By ~ 31

Author(s):

Julia Z. Rutman ◽

Lawrence E. Meltzer ◽

J. Roderick Kitchell ◽

Robert J. Rutman ◽

Philip George

Keyword(s):

Amino Acids ◽

Metal Ions ◽

Tricarboxylic Acid Cycle ◽

Rat Kidney ◽

Kidney Cortex ◽

Rat Kidney Cortex ◽

In Vitro Systems ◽

Cortex Slices ◽

Kidney Cortex Slices

The effect of metal ions on glucose formation from amino acids and glycolytic and tricarboxylic acid cycle intermediates has been examined in rat kidney cortex slices in vitro. Of the metals tested, only Mn++ and Ca++ have been shown to be stimulatory, while Zn++, Cu++, and Cd++ are inhibitory. The case of Mn++ activation is of particular interest because Mg++ ions are inactive in this system, despite the similarities usually observed in the in vitro systems. The stimulation of gluconeogenesis from α-keto acids is comparable for both Ca++ and Mn++, in contrast to the lack of a Mn++ effect with the homologous l-α-amino acids. Evidence is presented as to the possible significance of metal ions in regulating carbohydrate metabolism.

Download Full-text

FURTHER OBSERVATIONS ON UPTAKE OF S35-LABELLED SULFATE BY RENAL TISSUE IN VITRO

The Journal of General Physiology ◽

10.1085/jgp.39.6.893 ◽

1956 ◽

Vol 39 (6) ◽

pp. 893-908 ◽

Cited By ~ 7

Author(s):

Ingrith J. Deyrup

Keyword(s):

Rat Kidney ◽

Mammalian Species ◽

Renal Tissue ◽

Metabolic Inhibitors ◽

Kidney Cortex ◽

Rat Kidney Cortex ◽

Lower Vertebrates ◽

The One

Additional studies have been made of the accumulation of S35 by renal cortical tissue incubated in media containing radiosulfate. This process was found to occur in several mammalian species in addition to the rat, but was not observed as a significant occurrence in three species of lower vertebrates. In the case of rat renal tissue, S35 uptake was found to be sensitive to the pH and osmolar concentration of the medium. The character of the anions present in conjunction with K+ affected it as well. Various factors known to be related to in vitro accumulative processes, as well as to renal sulfate reabsorption by the intact dog, were tested on rat kidney cortex to assess the effect on radiosulfate uptake. In general, all substances tested (amino acids, metabolic intermediates, ATP, metabolic inhibitors, competitive inhibitors for PAH accumulation in vitro) were found to lessen S35 uptake, or to be without effect upon it. The one striking exception was phlorhizin, which enhanced markedly S35 uptake in vitro, as it does sulfate reabsorption in vivo. Some implications of these findings have been discussed.

Download Full-text

Identification of an apical \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{Cl}^{-}{/}\mathrm{HCO}_{3}^{-}\) \end{document} exchanger in rat kidney proximal tubule

AJP Cell Physiology ◽

10.1152/ajpcell.00084.2003 ◽

2003 ◽

Vol 285 (3) ◽

pp. C608-C617 ◽

Cited By ~ 47

Author(s):

Snezana Petrovic ◽

Liyun Ma ◽

Zhaohui Wang ◽

Manoocher Soleimani

Keyword(s):

Proximal Tubule ◽

Apical Membrane ◽

Rat Kidney ◽

Proximal Tubules ◽

Immunocytochemical Staining ◽

Kidney Cortex ◽

Rat Kidney Cortex ◽

Kidney Proximal Tubule ◽

Anion Transporter

SLC26A6 (or putative anion transporter 1, PAT1) is located on the apical membrane of mouse kidney proximal tubule and mediates [Formula: see text] exchange in in vitro expression systems. We hypothesized that PAT1 along with a [Formula: see text] exchange is present in apical membranes of rat kidney proximal tubules. Northern hybridizations indicated the exclusive expression of SLC26A6 (PAT1 or CFEX) in rat kidney cortex, and immunocytochemical staining localized SLC26A6 on the apical membrane of proximal tubules, with complete prevention of the labeling with the preadsorbed serum. To examine the functional presence of apical [Formula: see text] exchanger, proximal tubules were isolated, microperfused, loaded with the pH-sensitive dye BCPCF-AM, and examined by digital ratiometric imaging. The pH of the perfusate and bath was kept at 7.4. Buffering capacity was measured, and transport rates were calculated as equivalent base flux. The results showed that in the presence of basolateral DIDS (to inhibit [Formula: see text] cotransporter 1) and apical EIPA (to inhibit Na+/H+ exchanger 3), the magnitude of cell acidification in response to addition of luminal Cl– was ∼5.0-fold higher in the presence than in the absence of [Formula: see text]. The Cl–-dependent base transport was inhibited by ∼61% in the presence of 0.5 mM luminal DIDS. The presence of physiological concentrations of oxalate in the lumen (200 μM) did not affect the [Formula: see text] exchange activity. These results are consistent with the presence of SLC26A6 (PAT1) and [Formula: see text] exchanger activity in the apical membrane of rat kidney proximal tubule. We propose that SLC26A6 is likely responsible for the apical [Formula: see text] (and Cl–/OH–) exchanger activities in kidney proximal tubule.

Download Full-text