Mitochondrial injury: an early event in cisplatin toxicity to renal proximal tubules

1990 ◽  
Vol 258 (5) ◽  
pp. F1181-F1187 ◽  
Author(s):  
H. R. Brady ◽  
B. C. Kone ◽  
M. E. Stromski ◽  
M. L. Zeidel ◽  
G. Giebisch ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Proximal Tubule ◽  
Threshold Concentration ◽  
Early Event ◽  
Intact Cells ◽  
Mitochondrial Injury ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Early Effects ◽  
K Transport

Oxygen consumption (QO2) and net K+ transport were studied in rabbit proximal tubule suspensions to define the early effects of cisplatin on proximal tubule function. Cisplatin caused dose-dependent inhibition of QO2, which was delayed in onset. The concentration of cisplatin required for inhibition decreased as the duration of exposure was increased [40-min exposure, threshold concentration of 10(-4) M, inhibitor constant (Ki) of 10(-3) M; 4-h exposure, threshold concentration of 3 X 10(-5) M, Ki of 10(-4) M]. Both ouabain-sensitive and ouabain-insensitive QO2 were reduced, indicating inhibition of all adenosinetriphosphatases, including Na(+)- K(+)-ATPase activity. There was a parallel fall in ouabain-sensitive net K+ transport and cytosolic K+ content, confirming the latter observation. Na(+)-K(+)-ATPase activity was unchanged in cell membranes prepared by hypotonic lysis from cisplatin-treated tubules, indicating an indirect cytosol-dependent mechanism of enzyme inhibition. Nystatin-stimulated QO2 was reduced in cisplatin-treated tubules, excluding inhibition of Na+ entry as the mechanism of injury and suggesting mitochondrial injury. The latter was confirmed by measurement of carbonylcyanide-m-chlorophenylhydrazone (CCCP)-uncoupled QO2 in intact cells and ADP-stimulated (state 3) QO2 in digitonin-permeabilized tubules. Furthermore, by maximally stimulating mitochondrial respiration with CCCP and nystatin, it was possible to demonstrate mitochondrial injury at a time when basal QO2 and K+ transport were apparently normal. These data suggest that mitochondrial injury is a central event in cisplatin toxicity to the proximal tubule.

Proximal tubule Na+-K+-ATPase activity is inhibited during high-salt diet: evidence for DA-mediated effect

1988 ◽  
Vol 254 (6) ◽  
pp. F795-F801 ◽  
Author(s):  
A. Bertorello ◽  
T. Hokfelt ◽  
M. Goldstein ◽  
A. Aperia
Keyword(s):  
Atpase Activity ◽  
Proximal Tubule ◽  
Significant Inhibition ◽  
High Salt ◽  
Acid Decarboxylase ◽  
Thick Ascending Limb ◽  
Amino Acid Decarboxylase ◽  
Physiological Importance ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition

Locally produced dopamine (DA) causes a reversible and dose-dependent inhibition in Na+-K+-ATPase activity in rat proximal tubule (PT) segments [A. Aperia, A. Bertorello, and I. Seri. Am. J. Physiol. 252 (Renal Fluid Electrolyte Physiol. 21): F32–F45, 1987.]. To examine whether this effect might be of physiological importance, rats were given normal-salt (NS) or high-salt (HS) diet for 10 days. HS diet significantly increased Na excretion but did not alter glomerular filtration rate (GFR). Benserazide (Bz), an inhibitor of the enzyme L-aromatic amino acid decarboxylase (AADC) that converts L-dopa to DA, significantly attenuated the natriuresis in HS rats but had no effect on GFR. By use of immunofluorescence (IF) studies AADC was localized to the PT. Specific AADC IF was not observed in the medulla. In AADC-positive PT segments, Na+-K+-ATPase activity was significantly lower in HS rats than in NS rats (P less than 0.001). In AADC-negative medullary thick ascending limb, Na+-K+-ATPase activity was the same in NS and HS rats. If HS rats were given Bz just before study, PT Na+-K+-ATPase activity increased significantly and was not different from Na+-K+-ATPase activity in PT segments from NS rats. Bz had no significant effect on PT Na+-K+-ATPase activity in NS rats. In PT segments from Bz-treated rats, DA inhibited Na+-K+-ATPase activity already at a dose of 10(-8) M, whereas in segments from NS rats, significant inhibition of Na+-K+-ATPase activity was not observed until DA was increased to 10(-7) M.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Chemical aspect of the influence of cobalt ions on atpase activity

2000 ◽  
Vol 65 (7) ◽  
pp. 507-515 ◽  
Author(s):  
Ljubica Vujisic ◽  
Danijela Krstic ◽  
Jovan Vucetic
Keyword(s):  
Experimental Data ◽  
Plasma Membrane ◽  
Atpase Activity ◽  
Kinetic Analysis ◽  
Synaptic Plasma Membrane ◽  
Cobalt Ions ◽  
Dependent Inhibition ◽  
Ic50 Values ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

The influence of Co 2+ ions on the activities of Na+/K+-ATPase and Mg2+ -ATPase, enzymes from rat brain synaptic plasma membrane, was studied. The aim of this study was to investigate the inhibition of both ATPases activities byexposure tocobalt ions as a function of experimentally added CoSO4. The "free" Co2+ concentrations in the reaction mixturewere also calculated and discussed. CoSO4 induced a dose-dependent inhibition of both enzymes. The IC50 values of Co 2+, as calculated from the experimental curves, were 168 mM for Na+/K+-ATPase and 262 mMfor Mg 2+-ATPase, and for the recalculated free Co 2+ concentration 75.4 mM for Na+/K+-ATPase and 136 mM for Mg 2+-ATPase. The obtained linear Dixon's plot for Na+/K+-ATPase implies equilibium binding of cobalt with inhibitory sites on the enzyme. The kinetic parameters for both enzymes in presence and absence of CoSO4 were calculated from the experimental data. The results of the kinetic analysis show that inhibition of Na+/K+-ATPase induced by CoSO4 is non-competitive, and for Mg 2+-ATPase that there are two sites of different sensitivities or two different enzymes.

Effects of (-)-Menthol on Arylamine N-Acetyltransferase Activity in Human Liver Tumor Cells

2001 ◽  
Vol 29 (02) ◽  
pp. 321-329 ◽  
Author(s):  
Jing-Pin Lin ◽  
Yuh-Ching Li ◽  
Weng-Chuan Lin ◽  
Ching-Liang Hsieh ◽  
Jing-Gung Chung
Keyword(s):  
Tumor Cells ◽  
Liver Tumor ◽  
Human Liver ◽  
High Performance ◽  
Time Course ◽  
Tumor Cell Line ◽  
Intact Cells ◽  
Steady State Kinetic ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition

To evaluate whether or not (-)-menthol affects arylamine N-acetyltransferase (NAT) activity, we selected human liver tumor cell line (J 5) for examination. By using high performance liquid chromatography, NAT activity for acetylation of 2-aminofluorene (AF) was determined. (-)-Menthol displayed a dose-dependent inhibition to cytosolic NAT activity. Time-course experiments showed that NAT activity measured from intact human liver tumor cells was inhibited by (-)-menthol for up to 24 hrs. But in human liver tumor intact cells, the low doses (0.0032 and 0.032 mM) of (-)-menthol inhibited NAT activity andthe 0.32 mM (-)-menthol did not show any significant differences between control and (-)-menthol treated groups. Using standard steady-state kinetic analysis, it was demonstrated that (-)-menthol was a possible uncompetitive inhibitor (decrease Km and Vmax) to NAT activity in cytosols. This report is the first demonstration which showed (-)-menthol affect on human liver tumor cells NAT activity.

scholarly journals Early effects of uranyl nitrate on respiration and K+ transport in rabbit proximal tubule

1989 ◽  
Vol 36 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Hugh R. Brady ◽  
Bruce C. Kone ◽  
Robert M. Brenner ◽  
Steven R. Gullans
Keyword(s):  
Proximal Tubule ◽  
Uranyl Nitrate ◽  
Early Effects ◽  
K Transport

Inhibition of sarcolemmal Na+-K+-ATPase by palmitoyl carnitine: potentiation by propranolol

1985 ◽  
Vol 248 (1) ◽  
pp. H75-H81
Author(s):  
J. H. Kramer ◽  
W. B. Weglicki
Keyword(s):  
Bovine Serum Albumin ◽  
Atpase Activity ◽  
Cardiac Myocytes ◽  
Inhibitory Effect ◽  
Inhibition Activity ◽  
Irreversible Inhibition ◽  
Palmitoyl Carnitine ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Native sarcolemma (SL) from adult canine cardiac myocytes (Na+-K+-ATPase activity 74.2 +/- 3.0 mumol X mg-1 X h-1) was preincubated (10 min, 37 degrees C, pH 7.2) with 1) 20-600 microM palmitoyl carnitine, 2) 250 nM-2.5 mM propranolol, or 3) 20-600 microM palmitoyl carnitine plus propranolol at various concentrations (0.0, 0.025, 0.25, 0.5, 1.0, and 2.5 mM); after preincubation, Na+-K+-ATPase activity was assayed. Palmitoyl carnitine alone (series 1) had no effect on ATPase activity over the range of 20-400 microM but was inhibitory (30%) at 600 microM. Propranolol alone (series 2) did not alter ATPase activity at any concentration. When SL membranes were exposed to both palmitoyl carnitine and propranolol (series 3), a dose-dependent inhibition of ATPase activity was observed. The inhibitory effect was not reversed by 3.0% bovine serum albumin. Propranolol concentrations greater than 0.025 mM significantly inhibited the activity of SL exposed to palmitoyl carnitine (above 150 microM). Palmitoyl carnitine and propranolol do not have to be added simultaneously to produce combined inhibition. Activity was inhibited 50% when SL were pretreated with 100 microM palmitoyl carnitine followed by addition of 2.5 mM propranolol no inhibition occurred if preincubation conditions were reversed. Thus exposure of SL to propranolol and reported physiological levels of palmitoyl carnitine leads to irreversible inhibition of the Na+-K+-ATPase, which may be due to the combined membrane-perturbant actions of these amphipathic agents.

scholarly journals Role of 20-HETE in D1/D2 dopamine receptor synergism resulting in the inhibition of Na+-K+-ATPase activity in the proximal tubule

2007 ◽  
Vol 292 (5) ◽  
pp. F1435-F1442 ◽  
Author(s):  
Carolina Kirchheimer ◽  
Carlos F. Mendez ◽  
Andrea Acquier ◽  
Susana Nowicki
Keyword(s):  
Arachidonic Acid ◽  
Atpase Activity ◽  
Proximal Tubule ◽  
Rat Kidney ◽  
Threshold Concentration ◽  
Arachidonic Acid Metabolite ◽  
Control Activity ◽  
Per Se ◽  
Atpase Inhibition

Previous studies propose 20-hydroxyeicosatetraenoic acid (20-HETE), a major arachidonic acid metabolite of cytochrome P-450 (CYP), as a possible mediator of Na+-K+-ATPase inhibition by dopamine (DA). The aim of this study was to investigate the intracellular mechanisms involved in this effect and to elucidate the DA receptor associated with the 20-HETE pathway in the rat kidney. DA (10−5 M) inhibited Na+-K+-ATPase activity in microdissected tubular segments to 59.4 ± 3.8% of control activity. This response was suppressed by the CYP4A inhibitor 17-octadecynoic acid (10−6 M), which had no effect per se, thus confirming the participation of CYP arachidonic acid metabolites in DA-induced Na+-K+-ATPase inhibition. We next examined whether 20-HETE is involved in the signaling pathways triggered by either D1 or D2 receptors. Neither fenoldopam nor quinpirole (D1 and D2 agonists, respectively, both 10−5 M) modified Na+-K+-ATPase activity when tried alone. However, coincubation of a threshold concentration of 20-HETE (10−9 M) with fenoldopam resulted in a synergistic inhibition of Na+-K+-ATPase activity (66 ± 2% of control activity), while 20-HETE plus quinpirole had no effect. Furthermore, 20-HETE (10−9 M) synergized with forskolin (10−5 M) and with the diacylglycerol analog 1-oleoyl-2-acetoyl- sn-glycerol (OAG; 10−11 M; 62.0 ± 5.3 and 69.9 ± 2.0% of control activity, respectively), indicating a cooperative role of 20-HETE with the D1-triggered pathways. In line with these results, no additive effect was observed when OAG and 20-HETE were combined at concentrations which per se produced maximal inhibition (10−6 M). These results demonstrate that the inhibition of Na+-K+-ATPase activity by DA in the proximal tubule may be the result of the synergism between 20-HETE and the D1 signaling pathway.

scholarly journals Structure Confirmation and Evaluation of a Nonsteroidal Inhibitor of 17β-Hydroxysteroid Dehydrogenase Type 10

2018 ◽  
Vol 4 (3) ◽  
pp. 32 ◽  
Author(s):  
Sophie Boutin ◽  
Donald Poirier
Keyword(s):  
Hydroxysteroid Dehydrogenase ◽  
One Pot ◽  
Intact Cells ◽  
Hek 293 ◽  
Biological Assays ◽  
13C Nuclear Magnetic Resonance ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

17β-Hydroxysteroid dehydrogenase type 10 (17β-HSD10) is a steroidogenesis enzyme known for its potential role in Alzheimer’s disease. For comparison purposes between steroidal and nonsteroidal 17β-HSD10 inhibitors 1 and 2, respectively, we attempted the chemical synthesis of benzothiazole phosphonate derivative 2. Instead of a one-pot synthesis, we report a two-step synthesis with characterization of both imine intermediate 5 and final compound 2. Furthermore, complete assignation of 1H and 13C nuclear magnetic resonance (NMR) signals of 2 is provided, as we observed a divergence of NMR data with those published previously. Finally, biological assays showed that 1 and 2 inhibited the oxidation of estradiol (E2) into estrone (E1) by the 17β-HSD10 recombinant protein. However, in human embryonic kidney (HEK)-293 intact cells transfected with 17β-HSD10, only the steroidal inhibitor 1 induced a dose-dependent inhibition of E2 to E1 transformation.

Parathyroid hormone inhibits proximal tubule Na(+)-K(+)-ATPase activity

1992 ◽  
Vol 262 (2) ◽  
pp. F209-F216 ◽  
Author(s):  
C. P. Ribeiro ◽  
L. J. Mandel
Keyword(s):  
Atpase Activity ◽  
Proximal Tubule ◽  
Transepithelial Transport ◽  
Mitochondrial Activity ◽  
Maximal Effect ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Camp Generation ◽  
Dependent Inhibition ◽  
Camp Formation

arathyroid hormone (PTH) decreases the transepithelial transport of Na+ in the proximal tubule, an action ascribed to PTH-inhibited apical Na(+)-H+ exchanger-dependent Na+ entry. We tested the possibility that PTH could also diminish Na(+)-K(+)-ATPase-dependent Na+ exit. To dissociate effects on Na+ entry, studies were performed in a suspension of rat proximal tubules by measuring nystatin-stimulated ouabain-inhibitable O2 consumption (QO2) and monensin-stimulated ouabain-sensitive 86Rb uptake in the absence or presence of bovine PTH-(1-34) fragment. PTH inhibited the percent nystatin-stimulated QO2 in a concentration-dependent manner, with maximal effect at 10(-10) M. PTH-increased cAMP formation was seen at doses higher than 10(-9) M and was maximal at 10(-7) M. Dibutyryl cAMP (10(-4) M) only partially reproduced the PTH action on QO2. Angiotensin II (10(-6) M) blunted the effect of 10(-7) M PTH on QO2, although it did not change 10(-7) M PTH-dependent cAMP generation. The analogues PTH-(3-34) and [Nle8,Nle18,Tyr34]PTH-(3-34)-amide mimicked the effects of PTH-(1-34) on QO2 but did not affect cAMP formation. Monensin-stimulated ouabain-sensitive 86Rb uptake was inhibited by PTH in a dose-dependent manner, with 10(-7) M PTH being maximally inhibitory. Na(+)-K(+)-ATPase activity was also decreased by PTH-(3-34) in a concentration-dependent manner, with maximal effect occurring at 10(-8) M. Agonist-dependent inhibition of Na+ pump was not due to a decrease of mitochondrial activity, because mitochondrial uncoupled QO2 rates were the same in control and PTH-treated tubules.(ABSTRACT TRUNCATED AT 250 WORDS)

Ionic dependence of active Na-K transport: "clamping" of cellular Na+ with monensin

1987 ◽  
Vol 253 (1) ◽  
pp. F26-F33 ◽  
Author(s):  
R. S. Haber ◽  
T. A. Pressley ◽  
J. N. Loeb ◽  
F. Ismail-Beigi
Keyword(s):  
Atpase Activity ◽  
Liver Cell ◽  
Atp Hydrolysis ◽  
Hill Coefficient ◽  
Maximal Rate ◽  
Transport Capacity ◽  
Activation Curve ◽  
Intact Cells ◽  
K Transport ◽  
Ionophore Monensin

The Na+ ionophore monensin was used to study the Na+- and K+-dependence of ouabain-inhibitable 86Rb+ uptake in ARL 15 cells, a rat liver cell line. Graded concentrations of monensin rapidly induced incremental elevations of cellular Na+ that were stable for up to 2 h. In experiments in which cellular Na+ was thus “clamped” at various levels, the activation curve for ouabain-inhibitable 86Rb+ uptake as a function of intracellular Na+ was found to be steepest near basal Na+ levels (Hill coefficient approximately equal to 2.4), indicating that these cells can respond to relatively large changes in passive Na+ entry by increasing the race of Na-K pump function with only minimal increases in cellular Na+. Exposure of cells to monensin also permitted examination of the extracellular-K+ dependence of ouabain-inhibitable 86Rb+ uptake in the presence of saturating intracellular Na+ and yielded a Hill coefficient of approximately 1.5. The rate of ATP hydrolysis calculated from measurements of the maximal rate of ouabain-inhibitable 86Rb+ uptake in intact cells was similar to the enzymatic Vmax of the Na+-K+-ATPase in cell lysates, suggesting that the Na+-K+-ATPase activity in these broken-cell preparations closely reflects the functional transport capacity of the Na-K pump.

Role of Na+/H+ exchanger NHE3 in nephron function: micropuncture studies with S3226, an inhibitor of NHE3

2000 ◽  
Vol 278 (3) ◽  
pp. F375-F379 ◽  
Author(s):  
Volker Vallon ◽  
Jan-Robert Schwark ◽  
Kerstin Richter ◽  
Max Hropot
Keyword(s):  
Proximal Tubule ◽  
Proximal Convoluted Tubule ◽  
Tubuloglomerular Feedback ◽  
Thick Ascending Limb ◽  
Loop Of Henle ◽  
Luminal Membrane ◽  
Henle's Loop ◽  
Dependent Inhibition ◽  
Proximal Tubular ◽  
Dose Dependent Inhibition

Na+/H+ exchanger NHE3 is expressed in the luminal membrane of proximal tubule and thin and thick ascending limb of Henle's loop. To further define its role, the novel NHE3 inhibitor S3226 was employed in micropuncture experiments in nephrons with superficial glomeruli of anesthetized rats. Microperfusion of proximal convoluted tubule with S3226 revealed a dose-dependent inhibition of reabsorption (IC50 of 4–5 μM) with a maximum inhibition of 30% for fluid and Na+. During microperfusion of Henle's loop (last superficial proximal to first superficial distal tubular loop), no effect of S3226 (10 or 30 μM) on the reabsorption of fluid or Na+ was observed. Finally, S3226 (30 μM) left the tubuloglomerular feedback response unaltered as determined by the fall in proximal tubular stop-flow pressure in response to increasing loop of Henle perfusion rate. These studies indicate that NHE3 significantly contributes to fluid and Na+ reabsorption in proximal convoluted tubule. NHE3 appears not to significantly contribute to fluid or Na+reabsorption in the loop of Henle (including the S3 segment of proximal tubule) or macula densa control of nephron filtration.

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