Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The effect of chronic feeding of high salt diet on Na+, K(+)-ATPase activity of heart, liver, skeletal muscle, kidney and aorta was studied in the rat. 2. Groups of rats were either given tap water or 18 g/L saline to drink. After 7 days, 3 months or 12 months, the control group and salt loaded groups were sacrificed and Na+, K(+)-ATPase activity of heart, liver, skeletal muscle and kidney was determined by a coupled enzyme assay and that of the aorta by the K(+)-stimulated hydrolysis of 3-0-methylfluorescein phosphate. 3. Na+, K(+)-ATPase activity of heart, liver, skeletal muscle and aorta were not different between the experimental and control groups at 7 days. After 3 months, Na+, K(+)-ATPase activity of liver in salt-loaded group was higher than the control group. After 12 months of salt loading all tissues examined showed higher Na+, K(+)-ATPase activity compared to control groups. The activity of renal medulla of salt-loaded group was higher than that of control group as early as 7 days. 4. We conclude that long term salt loading causes an increase in the activity of Na+, K(+)-ATPase of kidney, heart, liver, muscle and aorta.
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PMID:The effect of high salt intake on Na+, K(+)-ATPase activity of tissues in the rat. 803 58

Endogenous Na(+)-pump specific inhibitors are present in the plasma, urine, and tissues of humans and animals. To date, the source of these inhibitors has not been rigorously defined. In the present study, large amounts of several Na(+)-pump specific inhibitors have been demonstrated to exist in the urine of rats raised on a regular chow diet and tap water. All of the inhibitor levels have been found to increase 1.5-8-fold by the surgical preparation of reduced renal mass (RRM) and one-kidney, one-clip (IK, IC) hypertension. These urinary inhibitors, however, except for the ouabain-like inhibitor which eluted from a high performance liquid chromatography C18 column at the same retention time as [3H]ouabain, disappeared within a week after switching the diet from regular diet (number 5001, PMI Feeds, Inc.) to pure synthetic diet (number 5755). The urinary level of the ouabain-like inhibitor decreased to only one-half of the level in the control rat raised on a regular diet. Two of these inhibitors were purified from both urine and diet by a combination of Amberlite XAD-2 adsorption chromatography, reverse phase low pressure liquid chromatography, and several high performance liquid chromatographies. Reverse phase high performance liquid chromatography, liquid secondary ion and gas-liquid mass spectrometries, and proton nuclear magnetic resonance spectroscopy identified these inhibitors as a stereoisomer of convalloside, probably neoconvalloside, and a mono-rhamnoside of periplogenin or its stereoisomer. These cardiac glycosides exhibited inhibitory potencies comparable to ouabain against ouabain-displacement from Na+,K(+)-ATPase and against 86Rb uptake into human erythrocytes, and they also exhibited cross-reactivity to anti-ouabain antibodies and anti-digoxin antibodies. These results clearly demonstrate that the principal source of most of the inhibitors in rat urine is the diet. The results suggest that the ouabain-like inhibitor may be derived from an endogenous origin.
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PMID:Identification of two cardiac glycosides as Na(+)-pump inhibitors in rat urine and diet. 816

In normal rabbit, immunolabeling of intercalated cells in the outer medullary collecting duct (OMCD) demonstrates band 3-like protein in the basolateral plasma membrane (15) and H(+)-adenosinetriphosphatase (H(+)-ATPase) in the apical plasma membrane and cytoplasmic vesicles (30). However, in type A intercalated cells in the cortical collecting duct (CCD), band 3-like protein is located primarily in multivesicular bodies and cytoplasmic vesicles (15), whereas H(+)-ATPase is present in cytoplasmic vesicles only in most intercalated cells (30). In this study, we observed the effect of chronic acid loading on immunolocalization of these transporters in the collecting duct. Adult New Zealand White rabbits received either normal tap water (controls) or 75 mM NH4Cl for 12 days plus eight daily gavages of 2-6 meq NH4Cl/kg body wt. At time of death, mean urine pH of acid-loaded animals was 5.96 (SD = 0.69), vs. 8.47 (SD = 0.07) in controls. Kidneys were fixed by in vivo perfusion and processed for light and electron microscopic immunoperoxidase localization of band 3-like protein and immunogold localization of H(+)-ATPase. In controls, band 3-like protein was largely confined to multivesicular bodies in the majority of positive-staining intercalated cells in the CCD and to the basolateral plasma membrane of intercalated cells in the OMCD. In acid-loaded rabbits, band 3 protein-positive intercalated cells in the inner CCD and the in the outer stripe of the OMCD (OMCDo) were strikingly stellate in form. Basolateral plasma membrane label was intensified, while the number of labeled multivesicular bodies was diminished. Morphometric analysis demonstrated an increase in the amount of basolateral plasma membrane in these intercalated cells. In control rabbits, H(+)-ATPase immunoreactivity in intercalated cells in the CCD was located predominantly over cytoplasmic vesicles. A minority of intercalated cells exhibited basolateral plasma membrane label, and only an occasional cell displayed apical plasma membrane label. In acid-loaded rabbits, H(+)-ATPase immunoreactivity was enhanced along the apical plasma membrane of intercalated cells in the inner CCD, and morphometric analysis demonstrated increased apical plasma membrane in band 3-positive intercalated cells in this segment. These results suggest that rabbits respond to acid loading via enhancement of both electrogenic proton secretion and Cl-/HCO3- exchange in intercalated cells in the inner CCD and the OMCDo.
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PMID:Activation of acid-secreting intercalated cells in rabbit collecting duct with ammonium chloride loading. 818 97

We studied the effect of chronic exposure (6 weeks and 6 months) of mice to drinking (tap) water containing 1.76% (0.06 M) aluminum lactate on some cytochemical properties of the blood-brain barrier (BBB). The plasmalemma-bound enzymatic activities of alkaline phosphatase (AP) and Ca(2+)-activated adenosine triphosphatase (Ca(2+)-ATPase) were studied at the ultrastructural level. Anionic sites were localized with cationized ferritin in a pre-embedding procedure and with cationic colloidal gold in a post-embedding procedure applied to brain samples embedded in Lowicryl K4M. Intravenously injected Evans blue and horseradish peroxidase (HRP) were used for evaluation of the functional state of the BBB. The results indicate that chronic exposure to aluminum does not noticeably affect barrier function of the endothelium of cerebral cortex blood microvessels. Focal leakage of larger than capillary microvessels (presumably arterioles and venules) was observed only in a few areas, such as the basal ganglia and amygdaloid nuclei. The localization of both enzymatic activities (AP and Ca(2+)-ATPase) in microvessels remained essentially unchanged. The localization of anionic sites was also unchanged except on the luminal surface of the endothelium of a few blood microvessels located in areas of the brain where leakage of the injected HRP was noted. In these vessels the injected HRP was often attached to the luminal surface of the endothelial cells, suggesting its increased stickiness. These data, compared with our previous observations on brain microvascular endothelial cells growing in vitro, indicate that cytotoxicity of aluminum is evidently less pronounced in the living organism, presumably due to action of detoxicating and regulatory mechanisms.
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PMID:Ultracytochemical studies of the effects of aluminum on the blood-brain barrier of mice. 828 66

We tested the hypothesis that cyclopiazonic acid (CPA), an inhibitor of the sarcoplasmic reticulum (SR) Ca(2+)-ATPase, increases intracellular Ca2+ concentration ([Ca2+]) in aortic myocytes and that the increase in [Ca2+]i is higher in aortic cells from deoxycorticosterone acetate (DOCA)-hypertensive rats. Male Sprague-Dawley rats, 250-300 g, underwent uninephrectomy, received a silastic implant containing DOCA (200 mg/kg) and had free access to water supplemented with 1.0% NaCl and 0.2% KCl. Control rats were also uninephrectomized, received normal tap water, but no implant. Intracellular Ca2+ measurements were performed in aortic myocytes isolated from normotensive (Systolic blood pressure = 120 +/- 3 mmHg; body weight = 478 +/- 7 g, N = 7) and DOCA-hypertensive rats (195 +/- 10 mmHg; 358 +/- 16 g, N = 7). The effects of CPA on resting [Ca2+]i and on caffeine-induced increase in [Ca2+]i after [Ca2+]i depletion and reloading were compared in aortic cells from DOCA and normotensive rats. The phasic increase in [Ca2+]i induced by 20 mM caffeine in Ca(2+)-free buffer was significantly higher in DOCA aortic cells (329 +/- 36 nM, N = 5) compared to that in normotensive cells (249 +/- 16 nM, N = 7, P < 0.05). CPA (3 microM) inhibited caffeine-induced increases in [Ca2+]i in both groups. When the cells were placed in normal buffer (1.6 mM Ca2+, loading period), after treatment with Ca(2+)-free buffer (depletion period), an increase in [Ca2+]i was observed in DOCA aortic cells (45 +/- 11 nM, N = 5) while no changes were observed in normotensive cells. CPA (3 microM) potentiated the increase in [Ca2+]i (122 +/- 30 nM, N = 5) observed in DOCA cells during the loading period while only a modest increase in [Ca2+]i (23 +/- 10 nM, N = 5) was observed in normotensive cells. CPA-induced increase in [Ca2+]i did not occur in the absence of extracellular Ca2+ or in the presence of nifedipine. These data show that CPA induces Ca2+ influx in aorta from both normotensive and DOCA-hypertensive rats. However, the increase in [Ca2+]i is higher in DOCA aortic cells possibly due to an impairment in the mechanisms that control [Ca2+]i. The large increase in [Ca2+]i in response to caffeine in DOCA cells probably reflects a greater storage of Ca2+ in the SR.
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PMID:The effects of cyclopiazonic acid on intracellular Ca2+ in aortic smooth muscle cells from DOCA-hypertensive rats. 923 14

The biliary pathway represents the major excretory route for copper (Cu). It has been suggested that glutathione (GSH) plays a role in this process. However, biliary secretion of endogenous Cu is unaffected in canalicular multispecific organic anion transporter (cmoat)/multi-drug resistance protein (mrp2)-deficient GY/TR- rats, which is a mutant rat strain expressing defective canalicular adenosine triphosphate (ATP)-dependent GSH-conjugate transport and which is unable to secrete GSH into bile. Secretion of Cu after iv Cu load is markedly impaired in GY/TR- rats when compared with normal Wistar (NW) rats. Administration, iv, of 65, 325, or 2300 nmol/100 g body wt CuSO4 dose-dependently increased Cu secretion in normal Wistar (NW) rats. Secretion rates in GY/TR rats were much lower and plateaued with higher loads at a level of about 35 nmol/h/100 g body wt. Clearance of an intravenous (iv) bolus of 64Cu (250 nmol/100 g body wt) was faster in GY/TR- rats than in controls, but secretion of 64Cu into bile was clearly reduced in the mutants. Specific activity of biliary Cu was similar in both groups. To investigate the removal of excess dietary Cu via bile, GY/TR and NW rats received water supplemented with Cu (CuSO4 8 mmol/L) for up to 12 weeks (Cu-fed) or tap water (controls). Cu feeding resulted in an increase of biliary Cu secretion from approximately 6 to approximately 30 nmol/h/100 g body wt within two weeks, both in NW and GY/TR- rats; Cu secretion also did not further increase during the course of the experiment. Hepatic Cu content was similar in NW and GY/TR- rats and progressively increased during Cu feeding. Our data indicate that biliary secretion of diet-derived Cu proceeds exclusively via a saturable Cu transporting system, which is distinct from cmoat/mrp2 and which is independent of biliary GSH. This transport may be mediated by the recently identified Cu-ATPase. In contrast, excess hepatic Cu after iv Cu load depends on cmoat/mrp2 activity for rapid removal. It is concluded that iv administered and dietary (endogenous) Cu is, in part, processed differently by rat liver, which might be related to differences in Cu redox state.
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PMID:Differences in hepatic processing of dietary and intravenously administered copper in rats. 932 20

Recently, the authors have shown that marked necrosis and fibrosis of myocardium were observed in rats given alkaline ionized water (AKW). To clarify the cause of myocardial lesions, the activities of myosin ATPase, actomyosin ATPase and creatine kinase (CK) in myocardium of rats given AKW at 15 weeks-old were compared with those in myocardium of rats given tap water (TPW). Furthermore, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of myocardiac myosin and isoelectric focusing (IEF) of myocardiac CK were performed which revealed a distinct difference between AKW and TPW groups. The activities of myosin ATPase and actomyosin ATPase in the AKW group were higher than those in the TPW group, and these elevated activities were caused by the degradation of myosin in the AKW group judging from the SDS-PAGE pattern of myosin. On the other hand, the activity of CK in the AKW group was lower than that in the TPW group, and the IEF pattern of CK showed leakage of myocardiac CK. These results indicate that increases in actomyosin ATPase activity and myosin ATPase activity, plus the decrease in CK activity caused the disorder of coupled reaction in male rats given AKW at 15 weeks-old. It is concluded that this disorder of coupled reaction may cause marked myocardiac necrosis and fibrosis in rats given AKW.
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PMID:Degradation of myocardiac myosin and creatine kinase in rats given alkaline ionized water. 952 51

An experiment performed in London nearly 120 years ago, which by today's standards would be considered unacceptably sloppy, marked the beginning of the calcium (Ca(2+)) signaling saga. Sidney Ringer [Ringer, S. (1883) J. Physiol. 4, 29-43] was studying the contraction of isolated rat hearts. In earlier experiments, Ringer had suspended them in a saline medium for which he admitted to having used London tap water, which is hard: The hearts contracted beautifully. When he proceeded to replace the tap water with distilled water, he made a startling finding: The beating of the hearts became progressively weaker, and stopped altogether after about 20 min. To maintain contraction, he found it necessary to add Ca(2+) salts to the suspension medium. Thus, Ringer had serendipitously discovered that Ca(2+), hitherto exclusively considered as a structural element, was active in a tissue that has nothing to do with bone or teeth, and performed there a completely novel function: It carried the signal that initiated heart contraction. It was a landmark observation, which should have immediately aroused wide interest. Unexpectedly, however, for decades it attracted no particular attention. Occasionally, farsighted pioneers argued forcefully for a messenger role of Ca(2+), offering compelling experimental evidence. Among them, one could quote L. V. Heilbrunn [Heilbrunn, L. V. (1940) Physiol. Zool. 13, 88-94], who contracted frog muscle fibers by applying Ca(2+) salts to their cut ends, but not to their surfaces. Heilbrunn correctly concluded that Ca(2+) had diffused from the cut ends to the internal contractile elements to elicit their contraction. One could also quote K. Bailey [Bailey, K. (1942) Biochem. J. 36, 121-139], who showed that the ATPase activity of myosin was strongly activated by Ca(2+) (but not by Mg(2+)), and concluded that the liberation of Ca(2+) in the neighborhood of the myosin controlled muscle contraction. Clearly, enough evidence was there, but only a handful of people had the vision to see it and to foresee its far-reaching implications. Perhaps no better example of clairvoyance can be offered than the quip by O. Loewy in 1959: "Ja Kalzium, das ist alles!"
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PMID:Calcium signaling: a tale for all seasons. 1183 Jun 54

The mechanism for acute toxicity of lead (Pb) in rainbow trout (Oncorhynchus mykiss) was investigated at Pb concentrations close to the 96 h LC50 of 1.0 mg dissolved Pb l(-1) (0.8-1.4, 95% C.I.) determined in dechlorinated Hamilton city tap water (from Lake Ontario, hardness=140 mg l(-1) CaCO(3)). Tissue Pb accumulation associated with death was highest in the gill, followed by kidney and liver. Significant ionoregulatory impacts were observed in adult rainbow trout (200-300 g) fitted with indwelling dorsal aortic catheters and exposed to 1.1+/-0.04 mg dissolved Pb l(-1). Decreased plasma [Ca(2+)], [Na(+)] and [Cl(-)] occurred after 48 h of exposure through to 120 h, with increases in plasma [Mg(2+)], ammonia, and cortisol. No marked changes in PaO(2), PaCO(2), pH, glucose, or hematological parameters were evident. Branchial Na(+)/K(+) ATPase activity in juvenile trout exposed to concentrations close to the 96 h LC50 was inhibited by approximately 40% after 48 h of Pb exposure. Calcium ion flux measurements using 45Ca as a radiotracer showed 65% inhibition of Ca(2+) influx after 0, 12, 24 or 48 h exposure to the 96 h LC50 concentration of Pb. There was also significant inhibition (40-50%) of both Na(+) and Cl(-) uptake, measured with 22Na and 36Cl simultaneously. We conclude that the mechanism of acute toxicity for Pb in rainbow trout occurs by ionoregulatory disruption rather than respiratory or acid/base distress at Pb concentrations close to the 96 h LC50 in moderately hard water.
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PMID:Ionoregulatory disruption as the acute toxic mechanism for lead in the rainbow trout (Oncorhynchus mykiss). 1279 13

A stimulatory role for insulin in the uptake of neutral amino acids has been reported for a variety of tissues. Here we examine the effect of insulin on L-dopa uptake by proximal tubule cells (PT cells) isolated from control and fructose-fed rats (FR-rats, 10% w/v fructose solution in tap water), a model of insulin resistance. Insulin (200 microU/ml) increased L-dopa uptake into PT cells by about 50% (705+/-186 vs.1117+/-140 pmol L-dopa/mg protein per minute) (p<0.05). The higher uptake correlated with a 40% increase in the number of high-affinity L-dopa transport sites (L-dopa 0.2 microM) (0.59+/-0.05 vs. 0.82+/-0.09 pmol L-dopa/mg protein per minute), without changing their affinity. The effect of insulin was not modified by ouabain (1 mM), nocodazole (1-10 microM) or colchicine (50-100 microM), whereas it was abolished by cytochalasin D or latrunculin B (both 1 microM). This suggests that the process is independent of Na(+),K(+)-ATPase activity or the microtubule network but that it requires the integrity of the actin cytoskeleton. L-dopa transport by the low-affinity transport sites (L-dopa 5 microM) was not affected by insulin, neither was the effect of insulin observed in PT cells isolated from FR-rats. In line with this, FR-rats showed lower renal L-dopa reabsorption as compared to control animals (81+/-4 vs. 51+/-9%). Taken together, our results support the involvement of insulin in the multifactorial regulation of renal L-dopa reabsorption.
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PMID:Insulin enhances L-dopa renal proximal tubule uptake: a regulatory mechanism impaired in insulin resistance. 1496 11


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