Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Guanylate cyclase of every fraction studied showed an absolute requirement for Mn2+ ions for optimal activity; with Mg2+ or Ca2+ reaction was barely detectable. Triton X-100 stimulated the particulate enzyme much more than the supernatant enzyme and solubilized the particulate-enzyme activity. 2. Substantial amounts of guanylate cyclase were recovered with the washed particulate fractions of cardiac muscle (63-98%), skeletal muscle (77-93%), cerebral cortex (62-88%) and liver (60-75%) of various species. The supernatants of these tissues contained 7-38% of total activities. In frog heart, the bulk of guanylate cyclase was present in the supernatant fluid. 3. Plasma-membrane fractions contained 26, 21, 22 and 40% respectively of the total homogenate guanylate cyclase activities present in skeletal muscle (rabbit), cardiac muscle (guinea pig), liver (rat) and cerebral cortex (rat). In each case, the specific activity of this enzyme in plasma membranes showed a five- to ten-fold enrichment when compared with homogenate specific activity. 4. These results suggest that guanylate cyclase, like adenylate cyclase, and ouabain-sensitive Na+ + K+-dependent ATPase (adenosine triphosphatase), is associated with the surface membranes of cardiac muscle, skeletal muscle, liver and cerebral cortex; however, considerable activities are also present in the supernatant fractions of these tissues which contain very little adenylate cyclase or ouabain-sensitive Na+ + K+-dependent ATPase activities.
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PMID:Guanylate cyclase. Subcellular distribution in cardiac muscle, skeletal muscle, cerebral cortex and liver. 1 Aug 90

Experiments were carried out to compare temporal changes in glomerular filtration rate (GFR), filtered Na+ load, and renal cortical (Na+ + K+)-adenosine triphosphatase (Na-K-ATPase) activity in the hypothyroid rat after administration of a single dose of triiodothyronine (T3) (50 microgram/100 g body wt). The cortex showed an increase in Na-K-ATPase at 24 h and progressive increases to a peak of 62% at 48 h. GFR and filtered Na+ load showed no changes at 24 and 48 h. At 72h, however, significant increases of 62 and 63% (per rat) were observed in GFR and filtered Na+ load, respectively. The results show that the early increase in Na-K-ATPase activity upon T3 treatment precedes the increases in GFR and filtered Na+ load, suggesting a direct effect of T3 on the regulation of Na-K-ATPase activity in the hypothyroid rat kidney cortex, rather than a secondary response to a primary increase in filtered Na+ load as proposed previously.
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PMID:Time course of the renal response to triiodothyronine in the rat. 21 8

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

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

We used metabolic, enzymatic, and functional end points to compare the protective properties of continuous warm and intermittent cold cardioplegic infusion in isolated, blood-perfused rat hearts. After excision, hearts (n = 12 per group) were preserved for 3 hours by one of the following cardioplegic procedures: (1) continuous infusion of warm (37 degrees C) blood cardioplegic solution prepared by mixing Fremes' solution with rat arterial blood in a ratio of 1:4, (2) continuous infusion of warm (37 degrees C) crystalloid cardioplegic solution prepared by mixing Fremes' solution with bicarbonate buffer solution in a ratio of 1:4, or (3) intermittent infusion of cold (20 degrees C) St. Thomas' Hospital cardioplegic solution number 2 infused for 3 minutes every 30 minutes during a 3-hour period of ischemia. In the continuous-infusion cardioplegic groups, the solution was infused through the aorta at a flow rate of 0.8 ml.min-1.gm-1 heart. At the end of the 3-hour preservation period, myocardial sodium-potassium adenosine triphosphatase activity (an index of ion-exchange activity) was assessed in six hearts in each group. The remaining hearts in each group were then aerobically perfused at 37 degrees C with arterial blood (from a support rat) for a further 50 minutes, during which time they were atrially paced at 320 beats/min. At the end of this period, left ventricular developed and end-diastolic pressures were assessed with an intraventricular balloon; the hearts were then freeze-clamped and taken for the measurement of tissue adenosine triphosphate and creatine phosphate content. Hearts (n = 6) aerobically perfused with blood for 50 minutes (no cardioplegic infusion) served as control preparations. At a balloon volume of 180 microliters, the mean final values for left ventricular developed pressure in the continuous warm blood, continuous warm crystalloid, and intermittent cold cardioplegic groups were 98 +/- 5 mm Hg (p < 0.05), 70 +/- 5 mm Hg, and 78 +/- 5 mm Hg, respectively. This was compared with 122 +/- 5 mm Hg in control hearts (p < 0.05 vs the rest). For left ventricular end-diastolic pressure, the corresponding values were 33 +/- 3 mm Hg, 32 +/- 6 mm Hg, and 14 +/- 4 mm Hg (p < 0.05), respectively. The control value was 16 +/- 3 mm Hg (p < 0.05 vs continuous warm blood and continuous warm crystalloid groups). Tissue content of adenosine triphosphate was similarly reduced to approximately 50% of control values in all groups, and creatine phosphate content fully recovered in all groups. Sodium-potassium adenosine triphosphatase activity was poorly preserved in continuous warm crystalloid-treated hearts (0.012 +/- 0.003 vs 0.030 +/- 0.008 mumol inorganic phosphate-mg-1.min-1.
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PMID:Continuous warm versus intermittent cold cardioplegic infusion: a comparison of energy metabolism, sodium-potassium adenosine triphosphatase activity, and postischemic functional recovery in the blood-perfused rat heart. 880 Jan 70

Our previous biochemical and mechanical studies have demonstrated an increase in Ca2+ sensitivity of cardiac myofilaments in ovariectomized rats. To test whether the body weight gain associated with ovariectomy contributed some effects to the changes in myofibrillar functions, the relations of pCa (-log Ca2+ molar concentration) to actomyosin adenosine triphosphatase (ATPase) activity of isolated myofibrillar preparations from 10-week pair-fed ovariectomized rats were compared with those from sham-operated controls. Despite similar body weights, the maximum myofibrillar ATPase activity was significantly lower in pair-fed ovariectomized rats as compared to that of sham-operated controls. In addition, the pCa-actomyosin ATPase relationship of pair-fed ovariectomized hearts still demonstrated a significant leftward shift in pCa50 (-log half-maximally Ca2+ activation) from that of sham-operated controls. To find out which hormone was responsible for the observed increase in myofibrillar Ca2+ sensitivity, different sex hormone supplemental regimens were administered to ovariectomized rats. Subcutaneous injection of estrogen (5 microg/rat) or estrogen plus progesterone (1 mg/rat) three times a week could effectively prevent the changes in body weight, heart weight, and uterine weight of the ovariectomized animals. Moreover, supplements of either estrogen or progesterone could prevent a decrease in maximum ATPase activity. In contrast, only the estrogen replacement could abolish the Ca2+ hypersensitivity of the myofilaments in these ovariectomized rats. These results suggest differential cardio-regulatory effects of ovarian sex hormones on the Ca2+ activation of the myofilaments.
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PMID:Estrogen supplement prevents the calcium hypersensitivity of cardiac myofilaments in ovariectomized rats. 1079 70

Cardiovascular disease, including atherosclerosis, is the leading cause of death in patients with diabetes worldwide; thus, it is a major medical concern. The endothelium contributes to the control of many vascular functions, and clinical observations show that it is a primary target for diabetic syndrome. To get better insight into the mechanisms underlying atherosclerosis, we studied the interspecific differences in the arterial metabolisms of two, Psammomys obesus and Gerbillus gerbillus, as well as Rattus norvegicus (Wistar rat), well known for its atheroresistance. Twenty-two enzymatic activities and six macromolecular substances were histochemically compared in the two desert species and in Wistar aortas (abdominal and thoracic) and arteries (femoral and caudal) embedded in a common block. In the healthy adult rodents, enzyme activities were very intense. They demonstrated that aortic myocytes are capable of various synthesis and catabolism processes. However, considering the frequency of atherosclerosis and its phenotypes, significant differences appeared between the species studied. Our comparative study shows that aortic atherosensitive animals have several common metabolic characteristics, which are found in Psammomys rich in metachromatic glycosaminoglycans (involved in the inhibition of lipolysis and in calcification of the organic matrix), reduced activity in enzymes related to the Krebs cycle (weakening energetic power), and low lipolytic enzyme, adenosine triphosphatase, and adenosine diphosphatase activities. However, the most fundamental pathophysiological difference is the low lipolytic power of the aorta of Psammomys when compared to Wistar rats. This characteristic determines its atherosensitivity and makes this animal model more applicable to the experimental development of atherosclerosis.
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PMID:Atherosclerosis and atherosensitivity in two southwest Algerian desert rodents, Psammomys obesus and Gerbillus gerbillus, and in Rattus norvegicus. 2305 58