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)

Luminal brush border and contraluminal basal-lateral segments of the plasma membrane from the same kidney cortex were prepared. The brush border membrane preparation was enriched in trehalase and gamma-glutamyltranspeptidase, whereas the basal-lateral membrane preparation was enriched in (Na+ + K+1)-ATPase. However, the specific activity of (Na+ + K+)-ATPase in brush border membranes also increased relative to that in the crude plasma membrane fraction, suggesting that (Na+ + K+)-ATPase may be an intrinsic constituent of the renal brush border membrane in addition to being prevalent in the basal-lateral membrane. Adenylate cyclase had the same distribution pattern as (Na+ + K+)-ATPase, i.e. higher specific activity in basal-lateral membranes and present in brush border membranes. Adenylate cyclase in both membrane preparations was stimulated by parathyroid hormone, calcitonin, epinephrine, prostaglandins and 5'-guanylylimidodiphosphate. When the agonists were used in combination enhancements were additive. In contrast to the distribution of adenylate cyclase, guanylate cyclase was found in the cytosol and in basal-lateral membranes with a maximal specific activity (NaN3 plus Triton X-100) 10-fold that in brush border membranes. ATP enhanced guanylate cyclase activity only in basal-lateral membranes. It is proposed that guanylate cyclase, in addition to (Na+ + K+)-ATPase, be used as an enzyme "marker" for the renal basal-lateral membrane.
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PMID:Preparation of renal cortex basal-lateral and bursh border membranes. Localization of adenylate cyclase and guanylate cyclase activities. 1 97

Dichloromethylene diphosphonate (Cl2MDP) was given at doses of 4 mg/kg and 10 mg/kg daily for 7 days to adult thyroparathyroidectomized rats fed a low calcium diet. Primary metaphyseal trabeculae in Cl2MDP-treated rats were more numerous and longer than in controls. The light and electron microscopic appearance of osteoblasts, osteocytes and osteoclasts were unaltered by Cl2MDP. Bone alkaline phosphatase was significantly elevated in rats given Cl2MDP but adenosine triphosphatase activity was unchanged. Bone fat-free weight, fat-free minus ash weight, and bone calcium and phosphorus concentration were reduced significantly in rats given 10 mg/kg Cl2MDP compared to controls. Bone magnesium concentration was significantly elevated in rats given 10 mg/kg Cl2MDP. Serum calcium and phosphorus concentration were lower in Cl2MDP-treated rats. These results suggest that Cl2MDP is capable of altering bone remodeling, enzyme activity and mineral content, without significantly altering bone cell morphology, independent of the effects of parathyroid hormone, calcitonin, and dietary calcium.
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PMID:Effect of dichloromethylene diphosphonate on morphology, enzyme activity, and ash content of bones of thyroparathyroidectomized rats. 14 84

The effect of calcitonin (CT) on Ca-ATPase activity in the plasma membrane fraction of rat liver was investigated. CT (80 MRC mU/100 g BW) administered subcutaneously to rats, caused a significant decrease in serum calcium, while increasing liver calcium. The administration of CT produced a rapid decrease of Ca-ATPase activity in the plasma membrane fraction of liver, whereas CT did not cause a significant alteration of p-nitrophenyl phosphatase activity. The maximal response of CT was obtained with 80 MRC mU/100 g BW. Meanwhile, the administration of imidazole (30 mg/100 g BW) which has a hypocalcemic effect, like CT, produced a significant increase in liver calcium and a corresponding fall in Ca-ATPase activity of the plasma membrane fraction. The reduction of Ca-ATPase activity produced by imidazole was significantly potentiated by the simultaneous administration of CT, and the rise in liver calcium was enhanced slightly. The present results suggest that the action of CT on liver calcium involves the decrease of Ca-ATPase activity in the plasma membrane of rat liver.
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PMID:Effect of calcitonin on Ca-ATPase activity of plasma membrane in liver of rats. 16 Aug 70

Free flow electrophoresis was employed to separate renal cortical plasma membranes into luminal (brush border microvilli) and contraluminal (basal-lateral membrane) fractions. During the separation adenylate cyclase activity was found to parallel the activity of Na+-K+-activated ATPase, an enzyme which is present in contraluminal but not in luminal membranes. In the basal-lateral membrane fraction the specific activities of adenylate cyclase and Na+-K+-activated ATPase were 4.4 and 4.6 times greater, respectively, than in the brush border fraction. The adenylate cyclase of the basal-lateral membrane fraction was specifically stimulated by parathyroid hormone which maximally increased enzyme activity eightfold. The biologically active (1-34) peptide fragment of paratyhroid hormone produced a 350% increase in adenylate cyclase activity. In contrast, calcitonin, epinephrine and vasopressin maximally stimulated the enzyme by only 55, 35 and 30%, respectively. These results indicate that adenylate cyclase, specifically stimulated by parathyroid hormone, is distributed preferentially in the contraluminal region of the plasma membrane of renal cortical epithelial cells.
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PMID:Distribution of parathyroid hormone-stimulated adenylate cyclase in plasma membranes of cells of the kidney cortex. 17 37

The effects of inhibition of bone resorption by the peptide hormone calcitonin have been studied at the level of the osteoclast. Although not epithelial, the osteoclast is polarized with the secretion of newly synthesized lysosomal enzymes and of acid occurring specifically at the apical pole, facing the bone compartment. The membranes composing the apical (ruffled-border) and basolateral domains contain topologically restricted antigens, a 100 x 10(3) Mr lysosomal membrane protein and the Na+,K(+)-ATPase, respectively. It was found that calcitonin induces a rapid (15-60 min) redistribution of the apical marker as well as of markers of the secretory compartment of the osteoclast (arylsulfatase and cation-independent mannose 6-phosphate (Man6P) receptors). The apical plasma membrane, in contrast to the basolateral membrane, is selectively internalized. This internalization leads to the disappearance of the ruffled border. The vesicular translocation of apical membranes is reminiscent of the events occurring in gastric oxyntic cells and in kidney tubule intercalated cells during the regulation of acid secretion. In parallel, the synthesis of both the lysosomal enzyme arylsulfatase and Man6P receptors is arrested. The products that were already present in the secretory pathway seem to be rerouted to intracellular vacuoles instead of being targeted to the plasma membrane, leading to marked accumulation of enzymes in the inhibited cells. These results suggest that the rapid inhibition of bone resorption by calcitonin involves the vesicular translocation of the apical membranes and the rapid arrest in the synthesis and secretion of lysosomal enzymes in osteoclasts.
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PMID:Selective internalization of the apical plasma membrane and rapid redistribution of lysosomal enzymes and mannose 6-phosphate receptors during osteoclast inactivation by calcitonin. 196 25

The effect of human parathyroid hormone-(1-34) (hPTH) and human calcitonin (hCT) on the activity of the Ca2(+)-extrusion pump in liver plasma membranes was studied. Both hormones were found to be potent inhibitors of Ca2+ transport and the related high-affinity (Ca2(+)-Mg2+)-ATPase activity, causing maximal inhibition of 25-30% at concentrations of 100 nM. Half-maximal inhibition was observed with 20 nM-hPTH and with 0.5 nM-hCT. By comparison, salmon calcitonin and intact bovine parathyroid hormone-(1-84) were inhibitory only at 10 microM. The effects of hCT and hPTH on the Ca2+ pump activity were not mimicked by cyclic AMP. Also, 10 microM of either hPTH-(1-34) or hCT did not alter the 45Ca2+ influx rate into isolated hepatocytes. We conclude that inhibition of Ca2+ efflux, rather than the stimulation of Ca2+ influx, may play a functional role in the control of hepatic calcium homeostasis by hPTH-(1-34) and hCT.
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PMID:Inhibition of the calcium pump by human parathyroid hormone-(1-34) and human calcitonin in liver plasma membranes. 215

Regulation of the acidity of osteoclasts was determined in situ on the endocranial surfaces of mouse calvaria using acridine orange, a fluorescent weak base. Osteoclasts could be identified by large size, multiple nuclei, relatively small numbers of cells, and the way and the extent to which they took up the dye. Nonosteoclastic cells were stained mainly in their nuclei and occasionally in a few lysosomes surrounding their nuclei, which were uniformly single in nonosteoclasts. Nuclei in osteoclasts were also stained, but the staining of the nuclei was partially masked by the intensity and completeness of the staining of the cytoplasm. In some cells the cytoplasmic staining appeared to be in discrete granules, giving the cytoplasm a bright, frothy appearance. This fluorescence was present in both treated and untreated cells and aided in identifying the osteoclasts. Acridine orange fluorescence at 624 nm intensity, and hence, osteoclast acidity, was increased by parathyroid hormone and prostaglandin E2. Parathyroid hormone-induced increases in acidity were inhibited by calcitonin, cortisol, sodium fluoride, and prostaglandin E2. Furthermore, osteoclast acidity was dependent largely or partially on maintenance of K+ and Na+ gradients, patent Na+ channels, chloride-bicarbonate exchange, and H+, K+-ATPase. These findings demonstrate that osteoclasts become acidified by mechanisms similar to those occurring in gastric parietal cells.
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PMID:Humoral and ionic regulation of osteoclast acidity. 243 48

Secretory granules of sheep thyroid parafollicular cells contain serotonin, a serotonin-binding protein, and calcitonin. Parafollicular cells, isolated by affinity chromatography, were found to secrete serotonin when activated by thyrotropin (TSH) or elevated [Ca2+]e. TSH also induced a rise in [Ca2+]i. We studied the effect of these secretogogues on the pH difference (delta pH) across the membranes of the secretory granules of isolated parafollicular cells. The trapping of the weak bases, acridine orange or 3-(2,4 dinitro anilino)-3'-amino-N-methyl dipropylamine (DAMP), within the granules was used to evaluate delta pH. In contrast to lysosomes, which served as an internal control, the secretory granules of resting parafollicular cells displayed a limited and variable ability to trap either acridine orange or 3-(2,4 dinitro anilino)-3'-amino-N-methyl dipropylamine; however, when parafollicular cells were stimulated with TSH or elevated [Ca2+]e, the granules acidified. Weak base trapping was also used to evaluate the ATP-driven H+ translocation into isolated parafollicular granules. The isolated parafollicular granules did not acidify in response to addition of ATP unless their transmembrane potential was collapsed by the K+ ionophore, valinomycin. Secretory granules isolated from TSH-treated parafollicular cells had a high chloride conductance than did granules isolated similarly from untreated cells. Furthermore, ATP-driven H+ translocation into parafollicular granules isolated from TSH-stimulated parafollicular cells occurred even in the absence of valinomycin. These results demonstrate that secretogogues can regulate the internal pH of the serotonin-storing secretory granules of parafollicular cells by opening a chloride channel associated with the granule membrane. This is the first demonstration that the pH of secretory vesicles may be modified by altering the conductance of a counterion for the H+ translocating ATPase.
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PMID:Thyrotropin induces the acidification of the secretory granules of parafollicular cells by increasing the chloride conductance of the granular membrane. 246 47

In order to examine the dynamics of ion regulation, osmoregulation, and plasma calcitonin during the parr-smolt transformation (smoltification), blood and gill tissue were collected from yearling coho salmon, Oncorhynchus kisutch, from February to October. Fish were kept in fresh water (FW) throughout this period. In addition, fish were exposed to seawater (SW) at the peak of smoltification in mid-April, and samples from these fish were collected until July. Plasma osmolality, gill Na+,K+-ATPase activity, plasma levels of calcitonin, and free and total calcium and magnesium were measured. SW adaptability of FW fish was assessed throughout the study by measurements of plasma osmolality following a 24-hr exposure to seawater. The greatest hypoosmoregulatory ability occurred in April-May, although SW-adapted fish had higher plasma osmolality than FW-adapted fish at all times. Gill Na+,K+-ATPase activity in FW-adapted fish increased from April to June and increased rapidly following exposure of fish to SW, and remained elevated in SW-adapted fish. Free plasma calcium and magnesium levels increased following SW exposure, but returned to prior levels within 1 week. Netting and confinement stress during sampling caused an increase in plasma osmolality and free calcium and magnesium levels in both FW- and SW-adapted fish. Changes in hypoosmoregulatory ability during smoltification and SW adaptation were correlated with changes in gill Na+,K+-ATPase activity. A sharp transitory peak in plasma calcitonin levels occurred early in smoltification (March) and in SW-adapted fish in June. Plasma calcitonin levels gradually increased in FW-adapted fish during the period of desmoltification. However, no change in plasma calcitonin levels occurred during SW-induced hypercalcemia, suggesting that the hormone does not play a major role in short-term plasma calcium regulation in coho salmon.
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PMID:Smoltification and seawater adaptation in coho salmon (Oncorhynchus kisutch): plasma calcium regulation, osmoregulation, and calcitonin. 254 13

The relationship between the serum levels of calcitonin (CT), Ca and P, and red blood cell Ca-ATPase (RBC Ca-ATPase) was investigated during Ca infusion given to 6 healthy volunteers. The following results were obtained: Ca infusion, during a 3-hour period, raised serum levels of CT, P and RBC Ca-ATPase with significant correlations between serum CT and RBC Ca-ATPase. The increase in RBC Ca-ATPase activity was accompanied by an appropriate decrease in K-Na-ATPase activity. This study supports the in vitro observations concerning the regulation of intracellular Ca level by CT. Activation of Ca-ATPase during Ca loading is important for red cell survival.
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PMID:Relationship between the serum levels of calcitonin, calcium, phosphorus and red blood cell Ca-ATPase during calcium infusion to healthy volunteers. 282 78


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