Na+K+ATPase activity and ouabain binding sites in erythrocytes in hyperthyroidism before and after treatment

1992 ◽  
Vol 15 (5) ◽  
pp. 363-367 ◽  
Author(s):  
C. De Riva ◽  
Su Chen ◽  
F. Virgili ◽  
F. Frigato
Keyword(s):  
Atpase Activity ◽  
Binding Sites ◽  
Ouabain Binding ◽  
Before And After

Reductions of myocardial Na-K-ATPase activity and ouabain binding sites in heart failure: prevention by nadolol

1993 ◽  
Vol 265 (6) ◽  
pp. H2086-H2093 ◽  
Author(s):  
T. H. Fan ◽  
R. P. Frantz ◽  
H. Elam ◽  
S. Sakamoto ◽  
N. Imai ◽  
...  
Keyword(s):  
Heart Failure ◽  
Atpase Activity ◽  
Binding Sites ◽  
Early Stage ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Adrenergic Stimulation ◽  
Ouabain Binding ◽  
Systemic Hemodynamic

To study the changes in myocardial digitalis binding sites in heart failure, we measured myocardial ouabain binding sites, Na-K-adenosinetriphosphatase (ATPase) activity, and ventricular muscle mechanical responses to acetylstrophanthidin in dogs with right-heart failure (RHF) produced by tricuspid avulsion and pulmonary artery constriction. Sham-operated dogs were studied as the control. RHF produced a significant decrease in ouabain binding sites in the right and left ventricular myocardium, which was accompanied by a proportional decrease in Na-K-ATPase activity. However, RHF and sham-operated dogs did not differ in systemic hemodynamic or right ventricular trabeculate muscle isometric contractile responses to acetylstrophanthidin. To determine whether chronic beta-adrenergic stimulation contributed to the development of Na-K-ATPase downregulation, we administered nadolol (40 mg/day) to a separate group of dogs during an early stage of RHF development. Nadolol effectively prevented the reduction of myocardial ouabain binding sites that occurred in RHF. Thus we conclude that myocardial ouabain binding sites and Na-K-ATPase activity are reduced in dogs with experimental heart failure and that these changes probably occur as a result of the attendant heightened sympathetic activity.

Sarcolemmal Na(+)-K(+)-ATPase: inactivation by neutrophil-derived free radicals and oxidants

1990 ◽  
Vol 259 (5) ◽  
pp. H1330-H1336 ◽  
Author(s):  
R. C. Kukreja ◽  
A. B. Weaver ◽  
M. L. Hess
Keyword(s):  
Free Radicals ◽  
Atpase Activity ◽  
Reperfusion Injury ◽  
Binding Sites ◽  
Human Neutrophils ◽  
Fenton’S Reagent ◽  
Inhibitory Effects ◽  
Ouabain Binding ◽  
Fenton's Reagent ◽  
Per Se

One of the targets of free radicals and neutrophil-derived oxidants that is known to be generated during ischemic-reperfusion injury of the myocardium is the sarcolemma. We therefore examined the susceptibility of sarcolemmal Na(+)-K(+)-ATPase and ouabain binding sites to O2-., H2O2,.OH, HOCl, NH2Cl, and stimulated neutrophils. O2-. generated from xanthine oxidase action on xanthine had no significant effect on Na(+)-K(+)-ATPase activity. The inhibition of Na(+)-K(+)-ATPase activity and ouabain binding by H2O2 was dependent on concentration and the time of incubation. H2O2 (10 mM) inhibited 80% of Na(+)-K(+)-ATPase activity at 90 min..OH generated by Fenton's reagent (200 microM Fe2+ + 5 mM H2O2) significantly decreased maximum binding of ouabain (43.06 +/- 1.45 to 31.96 +/- 2.37 pmol/mg) and was significantly protected by 5 mM mannitol (P less than 0.05). The dissociation constant of ouabain binding was unaffected by Fenton's reagent or H2O2. In contrast, lower concentrations of HOCl, NH2Cl, or PMA-stimulated human neutrophils (4 X 10(6) cells/ml) had significant inhibitory effects on Na(+)-K(+)-ATPase activity. We conclude that O-2. per se is not damaging to sarcolemmal Na(+)-K(+)-ATPase activity. The formation of H2O2 and the more destructive .OH or HOCl and NH2Cl disrupt sarcolemmal function by inhibiting Na(+)-K(+)-ATPase activity and destroying ouabain binding sites.

Depressed Na+-K+-ATPase activity in skeletal muscle at fatigue is correlated with increased Na+-K+-ATPase mRNA expression following intense exercise

2005 ◽  
Vol 289 (1) ◽  
pp. R266-R274 ◽  
Author(s):  
A. C. Petersen ◽  
K. T. Murphy ◽  
R. J. Snow ◽  
J. A. Leppik ◽  
R. J. Aughey ◽  
...  
Keyword(s):  
Gene Expression ◽  
Atpase Activity ◽  
Mrna Expression ◽  
Binding Sites ◽  
Time Course ◽  
Acute Exercise ◽  
Vastus Lateralis ◽  
Vastus Lateralis Muscle ◽  
Ouabain Binding ◽  
Atpase Gene

We investigated whether depressed muscle Na+-K+-ATPase activity with exercise reflected a loss of Na+-K+-ATPase units, the time course of its recovery postexercise, and whether this depressed activity was related to increased Na+-K+-ATPase isoform gene expression. Fifteen subjects performed fatiguing, knee extensor exercise at ∼40% maximal work output per contraction. A vastus lateralis muscle biopsy was taken at rest, fatigue, 3 h, and 24 h postexercise and analyzed for maximal Na+-K+-ATPase activity via 3- O-methylfluorescein phosphatase (3- O-MFPase) activity, Na+-K+-ATPase content via [3H]ouabain binding sites, and Na+-K+-ATPase α1-, α2-, α3-, β1-, β2- and β3-isoform mRNA expression by real-time RT-PCR. Exercise [352 (SD 267) s] did not affect [3H]ouabain binding sites but decreased 3- O-MFPase activity by 10.7 (SD 8)% ( P < 0.05), which had recovered by 3 h postexercise, without further change at 24 h. Exercise elevated α1-isoform mRNA by 1.5-fold at fatigue ( P < 0.05). This increase was inversely correlated with the percent change in 3- O-MFPase activity from rest to fatigue (%Δ3- O-MFPaserest-fatigue) ( r = −0.60, P < 0.05). The average postexercise (fatigue, 3 h, 24 h) α1-isoform mRNA was increased 1.4-fold ( P < 0.05) and approached a significant inverse correlation with %Δ3- O-MFPaserest-fatigue ( r = −0.56, P = 0.08). Exercise elevated α2-isoform mRNA at fatigue 2.5-fold ( P < 0.05), which was inversely correlated with %Δ3- O-MFPaserest-fatigue ( r = −0.60, P = 0.05). The average postexercise α2-isoform mRNA was increased 2.2-fold ( P < 0.05) and was inversely correlated with the %Δ3- O-MFPaserest-fatigue ( r = −0.68, P < 0.05). Nonsignificant correlations were found between %Δ3- O-MFPaserest-fatigue and other isoforms. Thus acute exercise transiently decreased Na+-K+-ATPase activity, which was correlated with increased Na+-K+-ATPase gene expression. This suggests a possible signal-transduction role for depressed muscle Na+-K+-ATPase activity with exercise.

(Na+-K+)-ATPase Activity and Ouabain-Binding Sites in the Cerebral Cortex of Young and Aged Fischer-344 Rats

Gerontology ◽  
1983 ◽  
Vol 29 (4) ◽  
pp. 242-247 ◽  
Author(s):  
Joseph C. LaManna ◽  
Gregory Doull ◽  
Kimberly McCracken ◽  
Sami I. Harik
Keyword(s):  
Cerebral Cortex ◽  
Atpase Activity ◽  
Binding Sites ◽  
Fischer 344 Rats ◽  
Ouabain Binding ◽  
Fischer 344

Ischemia-induced alteration of myocardial Na+-K+-ATPase activity and ouabain binding sites in hypercholesterolemic rabbits

1996 ◽  
Vol 127 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Wen-Jone Chen ◽  
Shoei-Yn Lin-Shiau ◽  
Huei-Chen Huang ◽  
Yuan-Teh Lee
Keyword(s):  
Atpase Activity ◽  
Binding Sites ◽  
Ouabain Binding

Chronic intermittent hypoxia and incremental cycling exercise independently depress muscle in vitro maximal Na+-K+-ATPase activity in well-trained athletes

2005 ◽  
Vol 98 (1) ◽  
pp. 186-192 ◽  
Author(s):  
R. J. Aughey ◽  
C. J. Gore ◽  
A. G. Hahn ◽  
A. P. Garnham ◽  
S. A. Clark ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Vastus Lateralis ◽  
Incremental Exercise ◽  
Peak Oxygen Consumption ◽  
Vastus Lateralis Muscle ◽  
Minor Effect ◽  
Moderate Altitude ◽  
Ouabain Binding ◽  
Before And After

Athletes commonly attempt to enhance performance by training in normoxia but sleeping in hypoxia [live high and train low (LHTL)]. However, chronic hypoxia reduces muscle Na+-K+-ATPase content, whereas fatiguing contractions reduce Na+-K+-ATPase activity, which each may impair performance. We examined whether LHTL and intense exercise would decrease muscle Na+-K+-ATPase activity and whether these effects would be additive and sufficient to impair performance or plasma K+ regulation. Thirteen subjects were randomly assigned to two fitness-matched groups, LHTL ( n = 6) or control (Con, n = 7). LHTL slept at simulated moderate altitude (3,000 m, inspired O2 fraction = 15.48%) for 23 nights and lived and trained by day under normoxic conditions in Canberra (altitude ∼600 m). Con lived, trained, and slept in normoxia. A standardized incremental exercise test was conducted before and after LHTL. A vastus lateralis muscle biopsy was taken at rest and after exercise, before and after LHTL or Con, and analyzed for maximal Na+-K+-ATPase activity [K+-stimulated 3- O-methylfluorescein phosphatase (3- O-MFPase)] and Na+-K+-ATPase content ([3H]ouabain binding sites). 3- O-MFPase activity was decreased by −2.9 ± 2.6% in LHTL ( P < 0.05) and was depressed immediately after exercise ( P < 0.05) similarly in Con and LHTL (−13.0 ± 3.2 and −11.8 ± 1.5%, respectively). Plasma K+ concentration during exercise was unchanged by LHTL; [3H]ouabain binding was unchanged with LHTL or exercise. Peak oxygen consumption was reduced in LHTL ( P < 0.05) but not in Con, whereas exercise work was unchanged in either group. Thus LHTL had a minor effect on, and incremental exercise reduced, Na+-K+-ATPase activity. However, the small LHTL-induced depression of 3- O-MFPase activity was insufficient to adversely affect either K+ regulation or total work performed.

Age-associated differential expression of Na+-K+-ATPase subunit isoforms in skeletal muscles of F-344/BN rats

1999 ◽  
Vol 87 (3) ◽  
pp. 1132-1140 ◽  
Author(s):  
Xiwu Sun ◽  
Murali Nagarajan ◽  
Philip W. Beesley ◽  
Yuk-Chow Ng
Keyword(s):  
Skeletal Muscle ◽  
Atpase Activity ◽  
Binding Sites ◽  
Skeletal Muscles ◽  
Brown Norway ◽  
Muscle Type ◽  
Ouabain Binding ◽  
High Affinity ◽  
Old Rats ◽  
Subunit Isoforms

Skeletal muscle expresses multiple isoforms of the Na+-K+-ATPase. Their expression has been shown to be differentially regulated under pathophysiological conditions. In addition, previous studies suggest possible age-dependent alterations in Na+-K+pump function. The present study tests the hypothesis that advancing age is associated with altered Na+-K+-ATPase enzyme activity and isoform-specific changes in expression of the enzyme subunits. Red and white gastrocnemius (Gast) as well as soleus muscles of male Fischer 344/Brown Norway (F-344/BN) rats at 6, 18, and 30 mo of age were examined. Na+-K+-ATPase activity, measured by K+-stimulated 3- O-methylfluorescein phosphatase activity, increased by ∼50% in a mixed Gast homogenate from 30-mo-old compared with 6- and 18-mo-old rats. Advancing age was associated with markedly increased α1- and β1-subunit, and decreased α2- and β2-subunit in red and white Gast. In soleus, there were similar changes in expression of α1- and α2-subunits, but levels of β1-subunit were unchanged. Functional Na+-K+-ATPase units, measured by [3H]ouabain binding, undergo muscle-type specific changes. In red Gast, high-affinity ouabain-binding sites, which are a measure of α2-isozyme, increased in 30-mo-old rats despite decreased levels of α2-subunit. In white Gast, by contrast, decreased levels of α2-subunit were accompanied by decreased high-affinity ouabain-binding sites. Finally, patterns of expression of the four myosin heavy chain (MHC) isoforms (type I, IIA, IIX, and IIB) in these muscles were similar in the three age groups examined. We conclude that, in the skeletal muscles of F-344/BN rats, advancing age is associated with muscle type-specific alterations in Na+-K+-ATPase activity and patterns of expression of α- and β-subunit isoforms. These changes apparently occurred without obvious shift in muscle fiber types, since expression of MHC isoforms remained unchanged. Some of the alterations occurred between middle-age (18 mo) and senescence (30 mo), and, therefore, may be attributed to aging of skeletal muscle.

Erythrocyte sodium fluxes, ouabain binding sites, and Na+, K+-ATPase activity in hyperthyroidism

Metabolism ◽  
1990 ◽  
Vol 39 (9) ◽  
pp. 952-957 ◽  
Author(s):  
Mano Arumanayagam ◽  
Dorothy MacDonald ◽  
C.S. Cockram ◽  
R. Swaminathan
Keyword(s):  
Atpase Activity ◽  
Binding Sites ◽  
Ouabain Binding ◽  
Erythrocyte Sodium

Selective induction of high-ouabain-affinity isoform of Na+-K+-ATPase by thyroid hormone

1988 ◽  
Vol 255 (6) ◽  
pp. E912-E919 ◽  
Author(s):  
R. S. Haber ◽  
J. N. Loeb
Keyword(s):  
Thyroid Hormone ◽  
Atpase Activity ◽  
Binding Sites ◽  
Binding Capacity ◽  
Specific Binding ◽  
Ouabain Binding ◽  
High Affinity ◽  
Mammalian Tissues ◽  
Dissociation Constant Kd ◽  
Crude Membrane Fraction

The administration of thyroid hormone is known to result in an induction of the Na+-K+-adenosinetriphosphatase (Na+-K+-ATPase) in rat skeletal muscle and other thyroid hormone-responsive tissues. Since the Na+-K+-ATPase in a variety of mammalian tissues has recently been reported to exist in at least two forms distinguishable by differing affinities for the inhibitory cardiac glycoside ouabain, we have studied the effects of 3,3',5-triiodo-L-thyronine (T3) treatment on these two forms of the enzyme in rat diaphragm. The inhibition of Na+-K+-ATPase activity in a crude membrane fraction by varying concentrations of ouabain conformed to a biphasic pattern consistent with the presence of two distinct isoforms with inhibition constants (KIs) for ouabain of approximately 10(-7) and 10(-4) M, respectively. Treatment of hypothyroid rats with T3 (50 micrograms/100 g body wt on 3 alternate days) nearly tripled that portion of the Na+-K+-ATPase activity corresponding to the high-ouabain-affinity form (increased by 178 +/- 24%), whereas the enzyme activity corresponding to the low-ouabain-affinity form was only slightly changed (increased by 20 +/- 5%). Measurement of the specific binding of [3H]ouabain to these membranes confirmed the presence of a class of high-affinity ouabain binding sites with a dissociation constant (Kd) of slightly less than 10(-7) M, whose maximal binding capacity was increased by T3 treatment by 185%. The calculated catalytic turnover associated with the high-affinity site was 70-80 molecules ATP hydrolyzed.site-1.s-1 and was unchanged by T3 treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

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