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)

Cells of sarcoma 180 and of Ehrlich's carcinoma were maintained by serial transplantation in male and female Swiss mice. Either estrogen, progesterone, or testosterone were injected im at doses of 1 mg/mouse. Ascitic fluid was aspirated at intervals of 1, 3, 6, 24, and 48 hours following hormone injections. Enzyme activities were analyzed by subjective grading according to the intensity of staining reaction. Estrogen produced enhancement of alkaline phosphatase activity in both types of cells in both sexes of mice. Progesterone produced increased alkaline phosphatase activity in both types of cells from female hosts but an inhibitory effect in male hosts' cells. Testosterone produced no change in enzyme activity in tumor cells of female hosts but in male hosts it inhibited enzyme activity of sarcoma 180 cells and activated activity in carcinoma cells. The effect of all 3 hormones on acid phosphatase activity was activation. With adenosine triphosphatase, estrogen stimulated the activity in both types of tumor in both sexes. Progesterone stimulated cells from male hosts with little or no effect on cells from female hosts. This enzyme was resistant to testosterone. Succinate dehydrogenase activity under similar conditions was different. Estrogen reduced this activity and progesterone produced some inhibition of activity. Testosterone inhibited the sarcoma cells but had no effect on carcinoma cells of either sex. Others have shown that sex hormones affect the enzyme activities beyond the target tissues, particularly in the liver, kidney, and pancreas. Different responses of the enzymes seemed to depend on the endogenous hormonal status of the mice.
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PMID:Enzymatic responses of transplanted tumour cells towards estrogen, progesterone and testosterone. 13 8

Diethylstilbestrol is a potent inhibitory agent of the Ca(2+)-ATPase activity of sarcoplasmic reticulum membranes. Other structurally related molecules, such as dienestrol or hexestrol having hydroxyl groups at para positions of the two benzene rings produce similar effects. The absence or derivatization of the hydroxyl groups as occurs with trans-stilbene or diethylstilbestrol dipropionate converts the structure in an activating agent of the enzyme. The Ca2+ transport profiles in the presence of the referred drugs reproduces the same behavior observed for the hydrolytic activity. There is also a clear indication of a membrane-mediated mechanism of these drugs. Ligand binding experiments at equilibrium indicate that diethylstilbestrol decreases the affinity for Ca2+ of the high affinity Ca2+ sites. Functional studies reveal that the activation/inhibition induced by these drugs is correlated with decreased levels of phosphoenzyme at steady state, and these levels are sensitive to the Ca2+ concentration. Chase experiments of [32P]phosphoenzyme and 45Ca2+ indicate a slight activation effect of diethylstilbestrol dipropionate on Ca2+ dissociation during the enzyme turnover. The use of different anthroyloxy derivatives of stearic acid as a fluorescent probe suggest that diethylstilbestrol and other inhibitory agents could be located close to the polar region of the lipid bilayer, which interferes with the Ca(2+)-binding sites, whereas the activators trans-stilbene and diethylstilbestrol dipropionate may have a deeper position into the membrane, which accelerates the Ca2+ translocation process.
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PMID:Effect of diethylstilbestrol and related compounds on the Ca(2+)-transporting ATPase of sarcoplasmic reticulum. 131 6

The effect of estrogen on plasma membrane was investigated using the primary cultured rat hepatocytes treated with carbon tetrachloride (CCl4) and the isolated plasma membrane of rat liver. 17 beta-Estradiol (E2), at concentrations of 10(-10) M to 10(-4) M, 10(-8) M to 10(-6) M and 10(-12) M to 10(-4) M, had an inhibitory effect on the CCl4-induced leakage of glutamic oxaloacetic transaminase, glutamic pyruvic transaminase and lactate dehydrogenase, respectively from primary cultured rat hepatocytes. Diethylstilbestrol, which caused inhibition at a dose of 10(-4) M, did not inhibit any enzyme leakage at any further concentrations of 10(-12) M to 10(-6) M. In the isolated plasma membrane of rat liver, Mg(2+)- and Na+,K(+)-adenosine triphosphatase activity was increased by E2 treatment at concentrations of 10(-6) M and 10(-4) M.
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PMID:Effect of estrogen on liver plasma membrane in rats. 147 13

We have compared the response of proton and water transport to oxytocin treatment in isolated frog skin and urinary bladder epithelia to provide further insights into the nature of water flow and H+ flux across individual apical and basolateral cell membranes. In isolated spontaneous sodium-transporting frog skin epithelia, lowering the pH of the apical solution from 7.4 to 6.4, 5.5, or 4.5 produced a fall in pHi in principal cells which was completely blocked by amiloride (50 microM), indicating that apical Na+ channels are permeable to protons. When sodium transport was blocked by amiloride, the H+ permeability of the apical membranes of principal cells was negligible but increased dramatically after treatment with antidiuretic hormone (ADH). In the latter condition, lowering the pH of the apical solution caused a voltage-dependent intracellular acidification, accompanied by membrane depolarization, and an increase in membrane conductance and transepithelial current. These effects were inhibited by adding Hg2+ (100 microM) or dicyclohexylcarbodiimide (DCCD, 10(-5) M) to the apical bath. Net titratable H+ flux across frog skin was increased from 30 +/- 8 to 115 +/- 18 neq.h-1.cm-2 (n = 8) after oxytocin treatment (at apical pH 5.5 and serosal pH 7.4) and was completely inhibited by DCCD (10(-5) M). The basolateral membranes of the principal cells in frog skin epithelium were found to be spontaneously permeable to H+ and passive electrogenic H+ transport across this membrane was not affected by oxytocin. Lowering the pH of the basolateral bathing solution (pHb) produced an intracellular acidification and membrane depolarization (and an increase in conductance when the normal dominant K+ conductance of this membrane was abolished by Ba2+ 1 mM). These effects of low pHb were blocked by micromolar concentrations of heavy metals (Zn2+, Ni2+, Co2+, Cd2+, and Hg2+). Lowering pHb in the presence of oxytocin (50 mU/ml) produced a transepithelial current (3 microA.cm-2 at pHb 5.5) which was blocked by 100 microM of Hg2+, Zn2+, or Ni2+ at the basolateral side, and by DCCD (10(-5) M) or Hg2+ (100 microM) from the apical side. The net hydroosmotic water flux (JH2O) induced by oxytocin in frog bladder sacs was blocked by inhibitors of H(+)-adenosine triphosphatase (ATPase). Diethylstilbestrol (DES 10(-5) M), oligomycin (10(-8) M), and DCCD (10(-5) M) prevented JH2O when present in the lumen. These effects cannot be attributed to inhibition of metabolism since cyanide (10(-4) M), or 2-deoxyglucose (10(-3) M) had no effect on JH2O.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Common channels for water and protons at apical and basolateral cell membranes of frog skin and urinary bladder epithelia. Effects of oxytocin, heavy metals, and inhibitors of H(+)-adenosine triphosphatase. 164 38

Two X-ray-sensitive mutants of CHO-K1 cells, xrs 5 and xrs 6, were characterised with regard to their responses to genotoxic chemicals, namely bleomycin, MMS, EMS, MMC and DEB for induction of cell killing, chromosomal aberrations and SCEs at different stages of the cell cycle. In addition, induction of mutations at the HPRT and Na+/K+ ATPase (Oua) loci was evaluated after treatment with X-rays and MMS. Xrs 5 and xrs 6 cells were more sensitive than wild-type CHO-K1 to the cell killing effect of bleomycin (3 and 13 times respectively) and for induction of chromosomal aberrations (3 and 4.5 times). In these mutants a higher sensitivity for induction of chromosomal aberrations to MMS, EMS, MMC and DEB was observed (1.5-3.5 times). The mutants also showed increased sensitivity for cell killing effects of mono- and bi-functional alkylating agents (1.7-2.5 times). The high cell killing effect of X-rays in these mutants was accompanied by a slight increase in the frequency of HPRT mutation. The xrs mutants were also more sensitive to MMS for the increased frequency of TGr and Ouar mutants when compared to wild-type CHO-K1 cells. Though bleomycin is known to be a poor inducer of SCEs, an increase in the frequency of SCEs in xrs 6 cells (doubling at 1.2 micrograms/ml) was found in comparison to no significant increase in xrs 5 or CHO-K1 cells. The induced frequency of SCEs in all cell types increased in a similar way after the treatment with mono- or bi-functional alkylating agents. MMS treatment of G2-phase cells yielded a higher frequency of chromatid breaks in the mutants in a dose-dependent manner compared to no effect in wild-type CHO-K1 cells. Treatment of synchronised mutant cells at G1 stage with bleomycin resulted in both chromosome- and chromatid-type aberrations (similar to the response to X-ray treatment) in contrast to the induction of only chromosome-type aberrations in wild-type CHO-K1 cells. The frequency of chromosomal aberrations chromosome and chromatid types) also increased with MMC treatment in G1 cells of xrs mutants. DEB treatment of G1 cells induced mainly chromatid-type aberrations in all cell types. The possible reasons for the increased sensitivity of xrs mutants to the chemical mutagens studied are discussed and the results are compared to cells derived from radiosensitive ataxia telangiectasia patients.
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PMID:Cytogenetical characterization of Chinese hamster ovary X-ray-sensitive mutant cells xrs 5 and xrs 6. III. Induction of cell killing, chromosomal aberrations and sister-chromatid exchanges by bleomycin, mono- and bi-functional alkylating agents. 247 28

The effects of ethinyl estradiol, a synthetic estrogen with cholestatic properties and a propensity to alter hepatocyte and ileal brush-border membrane fluidity, on lipid structure and Na+-K+-ATPase activity of rabbit small intestinal basolateral membranes were determined. Utilizing the fluorophores 1,6-diphenyl-1,3,5-hexatriene and DL-12-(9-anthroyl)stearic acid, increases in fluorescence anisotropy, the reciprocal of fluidity, were found in basolateral membranes and in membrane lipid liposomes isolated from ileum. Fluidity alterations were accompanied by a marked decrease in bilayer phospholipids (0.37 vs. 0.48 mumol/mg protein; P less than 0.01) and an increase in both the cholesterol-to-phospholipid molar ratio (0.85 vs 0.61; P less than 0.02) and membrane saturated fatty acid content. Estrogen-mediated physicochemical changes were associated with a significant reduction in ileal basolateral membrane Na+-K+-ATPase specific activity (100.0 vs. 185.8 nmol Pi.min-1.mg protein-1; P less than 0.02). Control values both for fluorescence anisotropy and for Na+-K+-ATPase specific activity were restored after in vitro membrane fluidization with benzyl alcohol. The data therefore indicate that ethinyl estradiol effects on basolateral membrane lipid dynamics are confined to the ileum and are associated with inhibition of Na+-K+-ATPase activity. These structural and functional changes appear to be related, in part, to specific modifications in the availability of phospholipid after estrogen treatment.
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PMID:Estrogen modulates ileal basolateral membrane lipid dynamics and Na+-K+-ATPase activity. 283 62

Polyacrylamide gel electrophoresis (PAGE) of partially purified ATPase from vacuoles of Saccharomyces carlsbergensis under non-dissociating conditions revealed 3 bands with ATPase activity. Further PAGE in dissociating conditions showed the similarity in composition of these 3 ATPase preparations. They were assumed to contain the same vacuolar ATPase exhibiting, however, different electrophoretic mobility due to the formation of enzyme complexes with different proteins and phospholipids. The ATPase preparation with the highest electrophoretic mobility contained 6 subunits of 75, 62, 16, 14, 12 and 9 kDa. Inhibitors of vacuolar ATPase [14C]DCCD and [14C]NEM bound to a 9 kDa polypeptide, while [14C]DES associated with a polypeptide of 75 kDa. A partially purified preparation of the vacuolar ATPase was not phosphorylated by [gamma-32P]ATP under conditions when plasma membrane ATPase formed a phosphorylated intermediate. Our results show that vacuolar H+-ATPase consists of several polypeptides, does not form the phosphorylated intermediate, and evidently represents a new type of H+-ATPase of yeast.
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PMID:What family of ATPases does the vacuolar H+-ATPase belong to? 286 63

Diethylstilbestrol (DES) was found to inhibit reversibly the hydrolysis of MgATP (80% at 100 microM) and proton pump activity (I50 approximately equal to 15 microM, complete at 100 microM) in chromaffin granule ghosts. The parallel inhibition suggests a tight kinetic coupling between the two activities. The Mg2+-ATPase activity, but not proton pumping, was partially restored by N,N'-dicyclohexylcarbodiimide, indicating that the two inhibitors in combination cause a partial uncoupling. The non-competitive type of inhibition shows that the action of DES is distal to the site of ATP binding and hydrolysis. Although unspecific, the interaction of DES with the chromaffin granule membrane seems primarily to affect the H+-ATPase.
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PMID:Inhibition of the H+-ATPase in bovine adrenal chromaffin granule ghosts by diethylstilbestrol. Evidence for a tight coupling between ATP hydrolysis and proton translocation. 289 26

Rat axial muscle previously has not been studied histochemically. We were interested in determining the fiber composition and fiber distribution in rat lateral longissimus (LL), the large epaxial dorsiflexor muscle active during sexual posturing in the female rat and to determine if estrogen replacement in ovariectomized rats would affect the histochemical profile. Staining for ATPase after acid preincubation at pH 4.5, pH 4.35, and after alkaline preincubation at pH 9.4 and staining for NADH-TR revealed that rat LL contains the three major types of fibers present in most mammalian hind limbs: fast-twitch glycolytic (FG); fast-twitch oxidative-glycolytic (FOG); and slow-twitch oxidative (SO). The muscle contains predominantly FG fibers; SO fibers are segregated superficially from L2--L6 where they comprise from 11 to 18% of the fiber population, and in an oxidative compartment in the medial deep region of L5 where they comprise 62% of all fibers. In the medial deep region of L5 most of the remaining fast fibers also contain oxidative enzyme. Spindles are most highly concentrated in this oxidative region of L5. Estrogen treatment did not affect the relative number, distribution, or diameter of the three muscle fiber types in rat LL. The concentration of SO and FOG fibers and spindles localized in the region of the lumbosacral joint is discussed by contrasting forceful movements (e.g., rump elevation during sexual behavior) with normal postural regulation.
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PMID:A histochemical study of lateral longissimus muscle in rat. 621 80

Diethylstilbestrol and dicyclohexylcarbodiimide inhibit the ATPase of the plasma membranes and the proton-pumping activity of the cells in a respiratory-deficient mutant of Saccharomyces cerevisiae. The effects of the inhibitors in vivo seem to be specific because neither the proton permeability nor the ATPase levels of the cells are affected. These results indicate that the yeast plasma-membrane ATPase corresponds to the proton pump of the cells. The fact that both inhibitors of the ATPase delay the fall of ATP levels which follows a block of fermentation indicates that ATPase function is one of the major ATP-consuming pathways in yeast. In addition, diethylstilbestrol prevents the fall of ATP levels produced by dinitrophenol, suggesting that this fall was caused by partial dissipation of the proton gradient and consequent stimulation of the proton-pumping ATPase.
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PMID:Effect of ATPase inhibitors on the proton pump of respiratory-deficient yeast. 624 54


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