inosinic-acid and 9-(2-hydroxy-3-nonyl)adenine

inosinic-acid has been researched along with 9-(2-hydroxy-3-nonyl)adenine* in 4 studies

Other Studies

4 other study(ies) available for inosinic-acid and 9-(2-hydroxy-3-nonyl)adenine

ArticleYear
AMP degradation in the perfused rat heart during 2-deoxy-D-glucose perfusion and anoxia. Part II: The determination of the degradation pathways using an adenosine deaminase inhibitor.
    Journal of molecular and cellular cardiology, 1996, Volume: 28, Issue:10

    Using the adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA), we determine the contribution of the adenosine pathway to the abundant purine release of two Langendroff-perfused rat heart models which differ particularly in inorganic phosphate (Pi) content: the 2-deoxy-D-glucose (2DG) perfused heart and the anoxic heart. We measure the release of coronary purines by high performance liquid chromatography, and the content of myocardial metabolites by 31P nuclear magnetic resonance spectroscopy. In the 2DG-perfused heart (2 mM for 45 min), the release of inosine [130 nmol/(min.gww)] is much larger than that of adenosine, and EHNA (50 microM) has little effect, showing that the pathway of inosine monophosphate (IMP) accounts for 97% of purine catabolism. In the anoxic heart (100% N2 for 45 min), where inosine and adenosine release are comparable in the absence of EHNA, the inhibitor reduces the release of inosine and catabolites from 50 to 20 nmol/(min.gww) and increases that of adenosine [from 30 to 55 nmol/(min.gww)], showing that the contributions of the IMP and adenosine pathways are 23 and 77%. The difference between the two models has been ascribed to the inhibition of AMP deaminase by Pi in the anoxic heart (Chen W, et al., 1996). We discuss the physiological significance of this heart-specific duality of degradation pathways.

    Topics: Adenine; Adenosine Deaminase; Adenosine Deaminase Inhibitors; Adenosine Monophosphate; Animals; Antimetabolites; Deoxyglucose; Enzyme Inhibitors; Heart; Hemodynamics; Hypoxia; In Vitro Techniques; Inosine Monophosphate; Myocardium; Perfusion; Phosphates; Purine Nucleosides; Rats; Rats, Sprague-Dawley

1996
Extracellular metabolism of adenine nucleotides and adenosine in the innervated skeletal muscle of the frog.
    European journal of pharmacology, 1991, May-02, Volume: 197, Issue:1

    The effects of coformycin, alpha,beta-methylene ADP, dipyridamole in the absence and presence of erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA), nitrobenzylthioinosine (NBTI), mioflazine and ouabain on the metabolic pathways of exogenously applied ATP and its metabolites in the frog innervated sartorius muscle were investigated. ATP catabolism yielded ADP, AMP, IMP, adenosine and inosine; the ecto-ATPase in situ was shown to be Ca(2+)- or Mg(2+)-activated with a Kmapp for ATP of 767 +/- 48 microM. AMP catabolism yielded IMP, adenosine and inosine; inosine was formed from either exogenous IMP or exogenous adenosine. Catabolism of AMP into IMP was blocked by coformycin, which enhanced adenosine and inosine formation from AMP. alpha,beta-Methylene ADP blocked adenosine formation from AMP and inosine formation from IMP; formation of IMP from AMP was enhanced by alpha,beta-methylene ADP. Complete blockade of AMP degradation was achieved with the simultaneous use of coformycin and alpha,beta-methylene ADP. Dipyridamole attenuated but did not completely block extracellular adenosine removal and inosine appearance in the bath. EHNA, applied in the presence of dipyridamole, did not cause any further attenuation of extracellular adenosine removal. Mioflazine, NBTI and ouabain did not affect adenosine disappearance from the bath. The results suggest that, in the frog innervated sartorius muscle, ATP can be sequentially catabolized into AMP which is then catabolized either into IMP or into adenosine. This extracellular degradation of AMP into IMP might then constitute a shunt-like mechanism to control the levels of adenosine formed from adenine nucleotides.

    Topics: Adenine; Adenine Nucleotides; Adenosine; Adenosine Deaminase; Adenosine Deaminase Inhibitors; Adenosine Diphosphate; Adenosine Triphosphate; Animals; Cations; Coformycin; Dipyridamole; In Vitro Techniques; Inosine Monophosphate; Kinetics; Muscles; Piperazines; Rana ridibunda; Sodium-Potassium-Exchanging ATPase; Thioinosine

1991
Activation of hepatocyte glycogen synthase by metabolic inhibitors.
    Archives of biochemistry and biophysics, 1986, Nov-01, Volume: 250, Issue:2

    Incubation of isolated rat hepatocytes with metabolic inhibitors causes an increase in the -glucose 6-P/+glucose 6-P activity ratio of glycogen synthase after decreasing ATP and increasing AMP levels. Concomitantly, the activity of phosphorylase is increased six-fold by the same treatment. This activation of both enzymes remains after gel filtration of the hepatocyte extracts. Addition of metabolic inhibitors to cells pretreated with an inhibitor of AMP-deaminase results in an accumulation of AMP and, simultaneously, in a further increase in the activation state of glycogen synthase. The correlation coefficient between the intracellular concentration of AMP and glycogen synthase activity is r = 0.93. It is proposed that the covalent activation of glycogen synthase by metabolic inhibitors can be triggered by changes in the level of the intracellular concentrations of adenine nucleotides.

    Topics: 2,4-Dinitrophenol; Adenine; Adenine Nucleotides; Animals; Atractyloside; Carbonyl Cyanide m-Chlorophenyl Hydrazone; Dinitrophenols; Enzyme Activation; Glycogen Synthase; Inosine Monophosphate; Liver; Phosphorylases; Rats

1986
Adenosine deaminase inhibition and myocardial adenosine metabolism during ischemia.
    Advances in myocardiology, 1985, Volume: 6

    It is generally assumed that myocardial adenine nucleotides are broken down (e.g., during ischemia) via AMP----adenosine----inosine, but contribution of the pathway AMP----IMP----inosine cannot be excluded. The catabolism of exogenously added adenosine (1-20 microM) was studied in isolated rat hearts. All catabolites (i.e., inosine, hypoxanthine, xanthine, and uric acid) were measured together with nonmetabolized adenosine. Even at low (1 microM) adenosine concentrations, deamination accounted for 60% of adenosine disappearing from the perfusate. The adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) (5 and 50 microM) was infused together with adenosine (5 microM). These two concentrations of EHNA inhibited deamination of exogenous adenosine by 65 and 91%, respectively. When hearts were made ischemic by reduction of perfusion pressure, addition of EHNA raised the adenosine release from 1.4 to 9.8 nmole/min per gram wet wt., but surprisingly, the release of inosine and oxypurines (8 nmole/min per g wet wt.) did not change. These results suggest that considerable breakdown of myocardial adenine nucleotides can occur via the AMP----IMP----inosine pathway instead of AMP----adenosine----inosine. The rate of total purine release is probably not a good measure of intracellular adenosine formation.

    Topics: Adenine; Adenosine; Adenosine Deaminase Inhibitors; Adenosine Monophosphate; Animals; Coronary Circulation; Coronary Disease; Inosine Monophosphate; Male; Myocardial Contraction; Myocardium; Nucleoside Deaminases; Purines; Rats; Rats, Inbred Strains

1985
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