Journal of cyclic nucleotide research最新文献_第2页

Effects of NaCl concentration on adenylate cyclase regulation by prostaglandins and guanine nucleotides. NaCl浓度对前列腺素和鸟嘌呤核苷酸调节腺苷酸环化酶的影响。

Journal of cyclic nucleotide research Pub Date : 1982-01-01

A C Howlett

{"title":"Effects of NaCl concentration on adenylate cyclase regulation by prostaglandins and guanine nucleotides.","authors":"A C Howlett","doi":"","DOIUrl":"","url":null,"abstract":"Na+ has been implicated as a requirement for the inhibition of adenylate cyclase by hormones and neurotransmitters. This study examines effects of salt concentration on neuroblastoma plasma membranes that occur in the absence of an inhibitory hormone. The adenylate cyclase response to stimulatory agonists (GTP plus PGE1 (3), PGI2 or PGE2) was influenced by NaCl. As the [NaCl] increased to 150 mM, an increase in maximal activity and a decrease in apparent affinity was observed. At concentrations above 150 mM, NaCl decreased prostaglandin affinity and progressively decreased maximal activation. The GTP requirement was not altered by 30 or 150 mM NaCl in the presence of PGE1 or PGI2. The rate of Gpp(NH)p stimulated activity increased as the [NaCl] was increased in the assay. This increased rate was conserved when membranes activated in the presence of Gpp(NH)p and NaCl were reassayed in the absence of guanine nucleotide or salt. The salt evoked rate increase was proportionally greater at submaximal MgCl2 concentrations. The concentration requirement for Mg2+ was reduced by salt for adenylate cyclase in the presence of GTP or Gpp(NH)p. However, the enzyme stimulated by hormone exhibited a Mg2+ requirement that was low in the absence of salt and could not be further reduced by increased [NaCl]. Alternative monovalent cations (150 mM Li+, K+, Cs+, but not choline or tetramethylammonium) and anions (SO4=) substituted for NaCl. The observed effects were reversible upon washing the membranes and neither ouabain nor tetrodotoxin altered the response. These effects may result from a conformational alteration of a protein particularly sensitive to neutral salts in the assay.","PeriodicalId":15497,"journal":{"name":"Journal of cyclic nucleotide research","volume":"8 2","pages":"91-102"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17810564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Activation of adenylate cyclase from purified platelet membranes by prostaglandin E1 and its inhibition by L-epinephrine: mechanistic effects. 前列腺素E1对纯化血小板膜腺苷酸环化酶的激活及其l -肾上腺素的抑制作用:机制作用。

Journal of cyclic nucleotide research Pub Date : 1982-01-01

M L Steer, S Braun, H A Lester, A Levitzki

{"title":"Activation of adenylate cyclase from purified platelet membranes by prostaglandin E1 and its inhibition by L-epinephrine: mechanistic effects.","authors":"M L Steer, S Braun, H A Lester, A Levitzki","doi":"","DOIUrl":"","url":null,"abstract":"Activation and inhibition of adenylate cyclase in purified human platelet membranes by hormones and guanyl nucleotides was studied. The rate constant of enzyme activation (kon) was measured using the GTP analog guanylimidodiphosphate (Gpp(NH)p), and the rate constant of enzyme deactivation (koff) was determined using the guanosine diphosphate analog guanosine 5'-0-(2-thio)-diphosphate (GDP beta S). PGE1 which was found previously (15) to accelerate kon has been found to accelerate also koff, from 0.1 sec-1 (6 min-1) to 0.2 sec-1 (12 min-1). The alpha 2-adrenergic inhibitory hormone 1-epinephrine did not alter kon, whether measured in the absence or presence of GTP, and also did not alter koff, whether measured under basal or PGE1-dependent GTP-ase activity at any concentration of GTP tested. These results suggest that the alpha 2-adrenergic receptor exerts its inhibitory effect on adenylate cyclase by a mechanism which does not involve its direct interaction with the GTP regulatory protein that is associated with the stimulatory hormone. These results support the view that the inhibitor involves the interaction of the inhibitory receptor with a GTP binding unit separate from the one mediating hormonal stimulation. This regulatory unit attenuates the adenylate cyclase activity either by interacting directly with the catalytic moiety or by modulating the interaction of the stimulatory GTP regulatory protein with the catalytic moiety.","PeriodicalId":15497,"journal":{"name":"Journal of cyclic nucleotide research","volume":"8 5","pages":"309-22"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18197989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Modulation of catecholamine activation of adenylate cyclase by the number of active beta-adrenergic receptors: theoretical considerations on the role of receptor diffusion in the cell membrane. 活化β -肾上腺素能受体数量对腺苷酸环化酶儿茶酚胺活化的调节:细胞膜中受体扩散作用的理论考虑。

Journal of cyclic nucleotide research Pub Date : 1982-01-01

S Swillens

引用次数: 0

Determination of plasma cyclic AMP with automated radioimmunoassay system (Gamma-flo). 自动放射免疫分析系统(γ -flo)测定血浆环AMP。

Journal of cyclic nucleotide research Pub Date : 1982-01-01

S T Eastman, G D Aurbach

引用次数: 0

Mechanism of control of the turkey erythrocyte beta-adrenoceptor dependent adenylate cyclase by guanyl nucleotides: a minimum model. 鸟苷核苷酸控制火鸡红细胞β -肾上腺素受体依赖腺苷酸环化酶的机制:一个最小模型。

Journal of cyclic nucleotide research Pub Date : 1982-01-01

S Braun, A M Tolkovsky, A Levitzki

{"title":"Mechanism of control of the turkey erythrocyte beta-adrenoceptor dependent adenylate cyclase by guanyl nucleotides: a minimum model.","authors":"S Braun, A M Tolkovsky, A Levitzki","doi":"","DOIUrl":"","url":null,"abstract":"Treatment of native turkey erythrocyte membranes with GMP and epinephrine produces a highly active but metastable form of adenylate cyclase which decays slowly to basal native state. The decay process is greatly facilitated by GTP and GDP beta S1, and is further enhanced by 1-epinephrine. This decay process is prevented reversibly by GMP. GppNHp, like GMP, prevents the decay process first reversibly, but with time stabilizes the highly active state in a persistently active state. The expression of the catalytic activity of the enzyme in the metastable state can also be inhibited reversibly by GTP, GDP beta S and GMP at all times during the decay process. The GppNHp stabilized form is not susceptible to nucleotide inhibition. Thus, two forms of the guanyl nucleotide unit are postulated to exist: an \"open\" and a \"closed\" form. In the presence of hormone and GTP, the enzyme shuttles between these two forms continuously. GMP and GppNHp favor the complete conversion to the \"open\" form in the presence of beta-agonist. Evidence is also presented for the existence of two GTP dependent processes which exhibit different apparent affinities towards the nucleotide: A high affinity GTP binding process is essential for the fruitful coupling between receptor and enzyme, and a low affinity GTPase site which is responsible for the termination of the hormonal signal.","PeriodicalId":15497,"journal":{"name":"Journal of cyclic nucleotide research","volume":"8 3","pages":"133-47"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17361887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Endothelium-induced relaxation by acetylcholine associated with larger rises in cyclic GMP in coronary arterial strips. 内皮诱导的乙酰胆碱松弛与冠状动脉条带环GMP升高相关。

Journal of cyclic nucleotide research Pub Date : 1982-01-01

S Holzmann

引用次数: 0

Stimulation of rat platelet adenylate cyclase by an endogenous calcium-dependent protease-like activity. 内源性钙依赖性蛋白酶样活性刺激大鼠血小板腺苷酸环化酶。

Journal of cyclic nucleotide research Pub Date : 1982-01-01

S Adnot, M Poirier-Dupuis, D J Franks, P Hamet

引用次数: 0

The effects of forskolin on adenylate cyclase in S49 wild type and cyc- cells. 福斯克林对S49野生型和cyc细胞腺苷酸环化酶的影响。

Journal of cyclic nucleotide research Pub Date : 1982-01-01

R W Downs, G D Aurbach

引用次数: 0

Inhibition of forskolin activated adenylate cyclase in hamster adipocyte membranes with prostaglandin E1 and clonidine. 前列腺素E1和可乐定对福斯克林活化的腺苷酸环化酶的抑制作用。

Journal of cyclic nucleotide research Pub Date : 1982-01-01

K K McMahon, R J Schimmel

{"title":"Inhibition of forskolin activated adenylate cyclase in hamster adipocyte membranes with prostaglandin E1 and clonidine.","authors":"K K McMahon, R J Schimmel","doi":"","DOIUrl":"","url":null,"abstract":"The diterpene forskolin has been shown by Seamon et al (Proc. Natl. Acad. Sci., USA, 78: 3363-3367, 1981) to elicit a large increase in adenylate cyclase activity and to permit further activation by GTP, GDP, sodium fluoride and hormones. The present communication documents forskolin activation of adenylate cyclase activity in hamster adipocyte membrane preparations and shows that the forskolin activated enzyme remains susceptible to inhibition by prostaglandin E1 and clonidine. Moreover, the presence of forskolin, while causing stimulation of adenylate cyclase activity does not appear to prevent the interactions of sodium chloride and GTP with the enzyme. Thus, sodium chloride increased both basal and forskolin stimulated adenylate cyclase activity while GTP decreased activities of the sodium chloride and forskolin activated enzymes. Attenuation of adenylate cyclase activity with clonidine and prostaglandin E1 was detected in the presence of forskolin and GTP and sodium chloride were required. The concentration of GTP required to decrease adenylate cyclase activity and to allow attenuation of the enzyme activity by prostaglandin E1 was not altered by the addition of forskolin.","PeriodicalId":15497,"journal":{"name":"Journal of cyclic nucleotide research","volume":"8 1","pages":"39-47"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17940411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Inhibition of forskolin-activated adenylate cyclase by ethanol and other solvents. 乙醇和其他溶剂对福斯克林活化腺苷酸环化酶的抑制作用。

Journal of cyclic nucleotide research Pub Date : 1982-01-01

R D Huang, M F Smith, W L Zahler

{"title":"Inhibition of forskolin-activated adenylate cyclase by ethanol and other solvents.","authors":"R D Huang, M F Smith, W L Zahler","doi":"","DOIUrl":"","url":null,"abstract":"Ethanol and a variety of solvents are known to activate basal and Gpp(NH)p- and hormone-stimulated adenylate cyclase. We report here that ethanol and other solvents inhibit the activation of adenylate cyclase by forskolin. In the presence of 10 microM forskolin, 2% ethanol gives about 20% inhibition and 5% ethanol gives 40% inhibition of enzyme activity. Analysis of ethanol inhibition at several forskolin concentrations suggests that inhibition is competitive versus forskolin. Thus the effect of ethanol is greater at low forskolin concentrations and minimal at high concentrations. In addition to ethanol, inhibition of forskolin activation was observed with acetone, n-butanol, t-butanol, dimethyl formamide, dioxane, methanol and n-propanol. Dimethyl sulfoxide was inhibitory only at high concentrations (10%). Since some solvent is needed to prepare forskolin solutions and to maintain solubility at higher concentrations, the inhibitory effects reported here are an important consideration in studies employing forskolin activation. To minimize solvent inhibition we recommend that dimethyl sulfoxide be used to prepare forskolin solutions. At concentrations of 5% and less, dimethyl sulfoxide gives little if any inhibition of forskolin activation and causes only small increases in basal activity.","PeriodicalId":15497,"journal":{"name":"Journal of cyclic nucleotide research","volume":"8 6","pages":"385-94"},"PeriodicalIF":0.0,"publicationDate":"1982-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17941831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0