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)

In ferret ventricular myocytes the rate of intracellular Ca concentration [Ca]i decline and relaxation is remarkably fast (compared with rabbit and rat) under conditions where both the sarcoplasmic reticulum Ca uptake and Na/Ca exchange are inhibited. Here we explore the possibility that this rapid [Ca]i decline in ferret cells is attributable to the sarcolemmal Ca ATPase by using carboxyeosin (a potent inhibitor of the sarcolemmal Ca-ATPase). We compare the effects of carboxyeosin with those of elevated extracellular [Ca] ([Ca]o) (a thermodynamic approach to limit Ca transport by the sarcolemmal Ca ATPase). In rabbit cells, carboxyeosin and high [Ca]o slowed [Ca]i decline similarly and both virtually abolished [Ca]i decline when mitochondrial Ca uptake was also inhibited. In ferret cells, carboxyeosin treatment produced these same effects on [Ca]i decline, but high [Ca]o did not mimic them. Moreover, only in carboxyeosin-treated ferret cells did additional inhibition of mitochondrial Ca uptake nearly abolish [Ca]i decline. We conclude that, carboxyeosin loading can inhibit the sarcolemmal Ca-ATPase in intact myocytes; that this pump seems likely to be responsible for the much faster relaxation observed in ferret cells after block of SR Ca accumulation and Na/Ca exchange transport and that the sarcolemmal Ca pump apparently has different characteristics in rabbit and ferret ventricular myocytes.
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PMID:Relaxation in ferret ventricular myocytes: role of the sarcolemmal Ca ATPase. 749 Dec 84

The biological potential of hepatic foci and tumors induced by peroxisome proliferators such as Wy-14,643 has been poorly characterized. In this study, male F-344 rats (n = 20/group/time point) were fed Wy-14,643 (0.1%) for 22, 37 or 52 weeks ('W-22', 'W-37' or 'W-52' respectively). At each time point some rats were killed and additional Wy-14,643-fed rats were switched to basal diet (Wy-14,643/'stopped') for up to 104 weeks (referred to as 'W-22/S', 'W-37/S' and 'W-52/S'). Homogeneous basophilic foci, but not clear cell foci, increased in number and size in W-37 and W-52 rats. In W-37/S rats, clear cell foci replaced basophilic foci as the most frequent phenotype. In serial section overlays, adenosine triphosphatase deficient foci accounted for only 16% of basophilic foci in W-52 rats and 16% of clear cell foci in W-37/S rats at 52 weeks. The replication of basophilic foci of W-37 rats was markedly increased (focal labeling index, FLI = 61.8% versus non-focal labeling index, LI = 11.4%; control LI = 0.8%). Clear cell foci from W-37/S rats at 52 weeks had a FLI of 1.6% (non-focal LI = 0.6%). Hepatocellular adenomas were increased in W-37 (11/20 rats and 0.8 tumors/rat) and W-52 groups (19/20 rats and 2.8 tumors/rat). Prevalence of hepatocellular carcinomas was elevated in W-52 rats (6/20 rats) but not in W-22 or W-37 rats. Following removal of Wy-14,643, prevalence of animals with malignant, metastatic hepatocellular carcinomas in W-52/S rats was similar to the prevalence in W-52 rats. However, Wy-14,643-induced adenomas completely regressed in W-37/S and W-52/S groups. In summary, significant morphological continuity between highly proliferative basophilic foci and hepatocellular tumors was identified, emphasizing the superiority of basophilia as a marker for lesions leading to development of hepatocellular neoplasia in rats fed Wy-14,643. An important biological distinction was noted between regressive hepatic adenomas and progressive hepatocellular carcinomas induced by a peroxisome proliferator.
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PMID:Biological potential of basophilic hepatocellular foci and hepatic adenoma induced by the peroxisome proliferator, Wy-14,643. 750 13

We investigated the possible central interaction of atrial natriuretic factor (ANF) and an endogenous Na+, K(+)-ATPase (Na-pump) inhibitor in normal rats. Release of an endogenous Na-pump inhibitor associated with deoxycorticosterone acetate-salt hypertension may be regulated in the anteroventral third ventricle (AV3V) area of the CNS. We reported earlier that bolus injection of synthetic 26-amino acid ANF (Arg101-Tyr126, 6 micrograms/250 g rat) into the lateral brain ventricle (ICV) promotes the appearance in the plasma of a Na-pump inhibitor in rats. To determine whether the AV3V area of the brain is involved in the ICV effect of ANF, we introduced electrolytic lesions in this area. This treatment abolished the appearance of the Na-pump inhibitor after intraventricular injection of ANF. To further localize the area and the pathways involved in the interaction of ANF and the Na-pump inhibitor, we produced bilateral medial coronal knife cuts designed to transect the medially coursing pathway through the periventricular tissue of the AV3V region between the level of the medial preoptic area and the anterior hypothalamic nuclei. These knife cuts also abolished the appearance of the Na-pump inhibitor after ICV injection of ANF. Our data to date indicate that centrally administered ANF promotes the appearance of a Na-pump inhibitor in the plasma. A central site of interaction between ANF and the Na-pump inhibitor appears to be the AV3V area and a medial pathway coursing caudally from the AV3V region.
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PMID:Effect of hypothalamic lesions on interaction of centrally administered ANF and the circulating sodium-pump inhibitor. 750 25

The mechanisms of proton secretion by the proximal brush-border membrane (BBM) were compared in carnivorous (dog), omnivorous (human, pig, rat), and herbivorous (rabbit, hamster) species. The activity of the proton pump (V-type bafilomycin-sensitive H(+)-adenosinetriphosphatase) and of the Na+/H+ exchanger (amiloride-sensitive quenching of acridine orange fluorescence), the two major proton secretion mechanisms, was measured. The enzymatic activity of the H(+)-adenosinetriphosphatase activity was measured in intact (endosomes) and solubilized (0.1% deoxycholate or Triton X-100) BBM vesicles isolated by conventional Mg2+ precipitation techniques. In all species, but not in humans, the fraction of the ATP turnover energizing the proton pump (bafilomycin-sensitive respiration) was also measured in isolated proximal tubules. Significant differences in acid transport mechanisms were noted between species, with the proton pump predominating in the BBM of carnivorous species and the Na+/H+ exchanger predominating in the BBM of herbivorous species. The fraction of respiration suppressible by bafilomycin in proximal tubules was also different in all the species considered. This may indicate a different organization of proximal H+ transport related to the species-specific menace to acid-base balance.
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PMID:Mechanisms of proximal proton secretion in BBM of herbivorous, omnivorous, and carnivorous species. 763 82

A description is provided of the fiber-type composition of several hindlimb muscles of the adult turtle, Pseudemys (Trachemys) scripta elegans. In addition, cross-section areas of each fiber type and an estimation of the relative (weighted) cross-section area (wCSA) occupied by the different fiber types are also provided. Seven muscles were selected for study, based on their suitability for future neurophysiological analysis as components of the segmental motor system, and on their homologies with muscles in other vertebrates. The test muscles were iliofibularis (ILF), ambiens (AMB), external gastrocnemius (EG), extensor digitorum communis (EDC), flexor digitorum longus (FDL), tibialis anterior (TA), and peroneus anterior (PA). Serial sections of these muscles were stained for myosin adenosine triphosphatase (ATPase), NADH-diaphorase, and alpha-glycerophosphate dehydrogenase (alpha-GPDH), thereby enabling fiber-type classification on the basis of indirect markers for contraction speed and oxidative (aerobic) vs. glycolytic (anaerobic) metabolism. All muscles contained three fiber types: slow oxidative (SO; possibly including some non-twitch tonic fibers); fast oxidative glycolytic (FOG); and fast glycolytic (Fg). There were at least 30% FOG and 50% FOG + Fg fibers in the seven muscles, the extreme distributions being the predominantly glycolytic ILF vs. the predominantly oxidative FDL muscle (ILF--15.5% SO, 35.2% FOG, 49.3% Fg vs. FDL--49.1% SO, 41.1% FOG, 9.8% Fg). As in other species, the test muscles exhibited varying degrees of regional concentration (compartmentalization) of the different fiber types. This feature was most striking in ILF. Pronounced compartmentalization was also observed in AMB, EG, PA, TA, and EDC, whereas the distribution of fiber types in the highly oxidative FDL was homogeneous. In five of the seven muscles, fiber size was ranked with Fg > FOG > SO. In terms of wCSA, which provides a coarse-grain measure of the different fiber types' potential contribution to whole muscle peak force, all muscles exhibited a higher Fg and lower SO contribution to cross-section area than suggested by their corresponding fiber-type composition. The largest relative increase in wCSA vs. fiber-type composition were in the ILF and AMB muscles. We conclude that the turtle hindlimb provides some interesting possibilities for testing for a division of labor among different muscles during different movements (e.g., sustained vs. ballistic), and for study of the behavior of the different fiber (and motor unit) types under normal and perturbed conditions. The relationships between the present results and previous findings on homologous muscles of the mammalian (cat, rat) and reptilian (lizard) hindlimb are discussed.
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PMID:Fiber-type composition of hindlimb muscles in the turtle, Pseudemys (Trachemys) scripta elegans. 766 37

Perfusion of liver of rats toxicated with galactosamine or thioacetamide with a 0.02% solution of picroliv (glycoside fraction of Picrorhiza kurroa) for 30 min (1 ml/min; 6 mg/rat), significantly reversed toxicant-induced changes in the activities of several enzymes. Galactosamine induced increases in the activities of alkaline phosphatase, gamma-glutamyl transpeptidase, acid ribonuclease, acid phosphatase, succinate dehydrogenase and decreases in the activities of Na(+)-K(+)-adenosine triphosphatase (ATPase) and glucose-6-phosphatase (reversed by 40-87%). Similarly, thioacetamide-induced inhibitions of the activities of Na(+)-K(+)-ATPase, Ca(++)-ATPase, Mg(++)-ATPase, succinate dehydrogenase and elevations in the activities of alkaline phosphatase, gamma-glutamyl transpeptidase, and acid ribonuclease were also significantly reversed. A significant reversal of the toxicants-induced decrease in [14C]-leucine incorporation was also observed. These results indicate that picroliv can also reverse D-galactosamine- or thioacetamide-induced hepatic damage in rats.
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PMID:Perfusion with picroliv reverses biochemical changes induced in livers of rats toxicated with galactosamine or thioacetamide. 825 34

SHR (spontaneously hypertensive rat) is the most popular genetic hypertensive model rat. Using the F2 progeny obtained from SHR and normotensive rats, for example, WKY (Wistar-Kyoto rat), many cosegregation studies to find the genes responsible for blood pressure have been done. In this review, we present some studies using F2 rats concerning candidate genes, renin, kallikrein, sodium potassium-ATPase, heat shock protein 70, angiotensin converting enzyme, phospholipase C-delta 1 and SA gene to show whether these genes really associate with blood pressure. We discuss the signification of these genes in the process of producing SHR and stroke-prone SHR from WKY. We hope these studies will lead to identify the mechanism of human essential hypertension.
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PMID:[Cosegregation studies in spontaneously hypertensive rats]. 832 Aug 40

Chicken chromosomal DNA encoding the Na+/K(+)-ATPase beta 1-subunit was cloned and characterized. Its exon-intron structure is identical to mammalian (human and rat) beta 1-subunit genes. The transcription initiation site, TATA box, and an ATTGG (antisense CCAAT) sequence follow approximately 1 kilobase of GC-rich 5' upstream sequence that contains many consensus sequences for transcription factors whose relative positions are conserved between human and chicken genes. When this beta 1-subunit gene was stably incorporated into mouse L cells and C2C12 cells, the avian beta 1-subunit was expressed under the control of the its own promoter.
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PMID:Structural analysis and expression of a chromosomal gene encoding an avian Na+/K(+)-ATPase beta 1-subunit. 838 29

The nude trait in the rat is transmitted in an autosomal recessive manner and is associated with thymic aplasia, T-cell deficiency, and hairlessness. Congenic rats homozygous for the RNU (Rowett nude) locus are important models in the study of inflammatory disease, tumor growth, and transplant rejection. The RNU locus has not been previously mapped, and the nature of the gene product is unknown. To determine the map location of this gene, a single F344.rnu/rnu (athymic nude congenic Fischer rat) male congenic rat was bred with 3 LEW/N (NIH stock Lewis rat) female rats to produce F1 progeny. Twelve F1 brother-sister breeding pairs were established. Forty-nine phenotypically nude F2 offspring (198 total) were obtained. Linkage analysis done on F2 DNA revealed highly significant cosegregation between the nude phenotype and eight polymorphic markers located on Chromosome (Chr) 10. The tightest linkages were with: MYH3 (embryonic, skeletal myosin heavy chain) and SHBG (sex hormone-binding globulin), giving 2 point lod scores of 20.2, and 20.0, respectively. The map order and map distances, determined by multipoint linkage calculations, were: RR24-(16.1 cM)-MYH3-(3.5 cM)-SHBG-(4.7 cM)-RNU-(11.9 cM)-F16F2-(24.1 cM)-CLATP (citrate lyase ATPase)-(2.4 cM)-ACE (angiotensin converting enzyme)/PPY (pancreatic polypeptide)-(14.1 cM)-RR1023. The position of the RNU locus in the rat corresponds closely with that of the recently reported nu locus in the mouse. This finding suggests that the nude phenotype in the rat and the mouse arise from defects in homologous genes.
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PMID:Genetic mapping of the athymic nude (RNU) locus in the rat to a region on chromosome 10. 842

The experiments described in this report reconcile some of the apparent differences in isoform-specific kinetics of the Na,K-ATPase reported in earlier studies. Thus, tissue-specific differences in Na+ and K+ activation kinetics of Na,K-ATPase activity of the same species (rat) were observed when the same isoform was assayed in different tissues or cells. In the case of alpha1, alpha1-transfected HeLa cell, rat kidney, and axolemma membranes were compared. For alpha3, the ouabain-insensitive alpha3*-transfected HeLa cell (cf. Jewell, E. A., and Lingrel, J. B. (1991) J. Biol. Chem. 266, 16925-16930), pineal gland, and axolemma (mainly alpha3) membranes were compared. The order of apparent affinities for Na+ of alpha1 pumps was axolemma approximately rat alpha1-transfected HeLa > kidney, and for K+, kidney approximately alpha1-transfected HeLa > axolemma. For alpha3, the order of apparent affinities for Na+ was pineal gland approximately axolemma > alpha3*-transfected HeLa, and for K+, alpha3*-transfected HeLa > axolemma approximately pineal gland. In addition, the differences in apparent affinities for Na+ of either kidney alpha1 or HeLa alpha3* as compared to the same isoform in other tissues were even greater when the K+ concentration was increased. A kinetic analysis of the apparent affinities for Na+ as a function of K+ concentration indicates that isoform-specific as well as tissue-specific differences are related to the apparent affinities for both Na+ and K+, the latter acting as a competitive inhibitor at cytoplasmic Na+ activation sites. Although the nature of the tissue-specific modulation of K+/Na+ antagonism remains unknown, an analysis of the nature of the beta isoform associated with alpha1 or alpha3 using isoform-specific immunoprecipitation indicates that the presence of distinct beta subunits does not account for differences of alpha1 of kidney, axolemma, and HeLa, and of alpha3 of axolemma and HeLa; in both instances beta1 is the predominant beta isoform present or associated with either alpha1 or alpha3. However, a kinetic difference in K+/Na+ antagonism due to distinct betas may apply to alpha3 of axolemma (alpha3beta1) and pineal gland ( alpha3beta2).
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PMID:Tissue-specific versus isoform-specific differences in cation activation kinetics of the Na,K-ATPase. 863 45


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