共查询到20条相似文献,搜索用时 15 毫秒
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A simple method for the preparation of [32P]adenosine 3′,5′-cyclic monophosphate (cyclic AMP) is described. A culture of Escherichia coli mutant deficient in cyclic AMP receptor protein is incubated with [32P]orthophosphate of known specific activities (up to 4000 Ci/mole) for several cell doublings. 1012 cells of this mutant excrete approximately 1.4 μmoles of cyclic AMP/hr. The extracellular cyclic AMP can be purified by adsorption to charcoal, chromatography on an alumina plate, and paper chromatography. 相似文献
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M Mikuni Y Saito T Koyama M Daiguji I Yamashita K Yamazaki M Honma M Ui 《Life sciences》1978,22(8):667-672
Circadian variations in plasma cyclic AMP and cyclic GMP were studied in thirteen male subjects (20–22 years old) under controlled invironmental condition. Plasma collections were made every six hours. Cyclic AMP and cyclic GMP were determined by radioimmunoassay. Individual values of plasma cyclic AMP at 0800 are between 13.0 and 25.8 pmole/ml, and cyclic GMP between 2.5 and 7.0 pmole/ml. Cyclic AMP demonstrated the circadian variation with the maximum level at 1400 and the minimum at 0200, and cyclic GMP with the highest level at 1400 and the lowest level at 0800. 相似文献
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Morphine administration (20 mg/kg) to awake rhesus monkeys which had been chronically implanted with catheters for aspiration of cerebrospinal fluid (CSF) produced a significant elevation in the CSF level of guanosine-3′, 5′-cyclic monophosphate (cGMP). Additionally, biopsies of cerebral and cerebellar cortex were taken from anesthetized monkeys given 20 mg/kg of morphine sulfate. Only cerebellar cGMP levels changed significantly, showing a 35% decrease relative to anesthetized controls. Although the controlling factors of brain tissue and CSF cGMP levels are poorly understood, the possibility of a reciprocal relationship between cGMP levels in certain brain regions and in CSF under some conditions is discussed. 相似文献
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K N Prasad G Becker K Tripathy 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1975,149(3):757-762
There are phosphodiesterase activities in both particulate and supernatant fractions which hydrolyze guanosine 3',5'-cyclic monophosphate (cGMP) and adenosine 3',5'-cyclic monophosphate (cAMP) with an apparent Km of 2-8 muM and with an apparent Km of 44-222 muM. 4-(3-Butoxy-4-methoxybenzyl-2-imidazolidinone (RO20-1724) did not inhibit cGMP phosphodiesterase activity in homogenates of mouse neuroblastoma cells, but markedly inhibited cAMP phosphodiesterase activity. Papaverine and theophylline inhibited both cGMP and cAMP phosphodiesterase activities to about the same extent. The former was more potent than the latter. The specific activity of cGMP phosphodiesterase as a function of protein concentrations first increased and then decreased. The specific activity of cAMP phosphodiesterase decreased under a similar experimental condition. 相似文献
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A comparison has been made between the capacity to hydrolyse 2′,3′-cyclic adenosine monophosphate and 3′,5′-cyclic adenosine monophosphate in subcellular fractions of normal and neoplastic (lymphosarcoma) spleen of C57BL mice. The effect of X-irradiation on these activities was tested. Subcellular fractionation of normal and lymphosarcoma spleen points to a different overall localization of the enzymes. The 2′,3′-cyclic nucleotide phosphodiesterase (2′,3′-cAMPase) has its highest specific activity in the particulate fractions of the cell, while the data on 3′,5′-cyclic nucleotide phosphodiesterase (3′,5′-cAMPase) show the highest activity in the soluble fraction. The 2′,3′-cAMPase activity is higher in the tumor as compared to the normal tissue, while the opposite holds for 3′,5′-cAMPase. Total body irradiation of normal mice with a dose of 600 rads of X-rays, results in a clear drop in 2′,3′-cAMPase 48 hours after the exposure. The 3′,5′-cAMPase is hardly affected at this time. Neither imidazol nor Mg++ has any influence on the 2′,3′-cAMPase. The pH optimum for 3′,5′-cAMPase and 2′,3′-cAMPase appears to be 7.7 and 6.2 respectively. This report suggests a no-identity of the two enzymes in mouse spleen, a situation different from that found in certain plants. 相似文献
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Díaz Enrich MJ Villamarín JA Ramos Martínez JI Ibarguren I 《Analytical biochemistry》2000,285(1):105-112
Two fast and sensitive methods for the determination of cAMP and cGMP levels in mantle tissue of the sea mussel Mytilus galloprovincialis Lmk. are described. Both methods use ion-pair high-performance liquid chromatography with diode array detection. The use of the diode array detector permitted the simultaneous detection of the absorbance at two different wavelengths and the obtaining of the UV absorption spectrum for each detected peak, confirming peak purity and identity. Method precision was good. The detection limit for both nucleotides was 2.5 pmol (signal-to-noise ratio = 4 at 254 nm). Previous to the injection onto the chromatograph, both nucleotides were purified by precipitation of the adenine and guanine 5'-ribonucleotides with ZnSO(4)-Na(2)CO(3). The supernatant obtained was subsequently passed over an anion-exchange column (AG l-X8 formate form resin). Early results seem to indicate that there is a seasonal variation in the contents of both cyclic nucleotides in mantle tissue. Such variation is probably related to the annual gametogenic cycle. 相似文献
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R P Bodnaryk 《Canadian journal of biochemistry》1976,54(11):957-962
Within 1 h after topical application of a convulsive dose (4 mug per fly, 47 mg/kg) of p,p'-dichlorodiphenyltrichloroethane (DDT) to the adult male of Sarcophaga bullata Parker, guanosine 3',5'-cyclic monophosphate (cyclic GMP) levels rose by 71.5% (P less than 0.05) in the head, 159.5% (P less than 0.01) in the thorax, and 23.4% (P greater than 0.05) in the abdomen compared to controls. Adenosine 3',5'-cyclic monophosphate (cyclic AMP) levels were not significantly affected by the DDT treatment. A convulsive dose (100 mug per larva, 250 mg/kg) of DDT applied to larvae of Mamestra configurata Wlk. caused the whole body level of cyclic GMP to rise by 81.6% (P less than 0.01) after 1 h, and by 95.9% (P less than 0.01) after 3 h. Levels of cyclic AMP were not affected. A hypothesis is advanced suggesting that an abnormally high rate of discharge of acetylcholine (and in the later stages of poisoning, its actual accumulation) at central cholinergic synapses causes cyclic GMP levels to rise, perhaps in post-synaptic cells. The elevated cyclic GMP-cyclic AMP ratio found in DDT-poisoned insects may be of fundamental importance in the complex sequence of events leading to tremor, hyperexcitability, paralysis, and death. 相似文献
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Adenosine 3',5'-cyclic phosphate (cAMP) is efficiently hydrolyzed at pH 7, 50 degrees C by use of [Co-(trien) (H2O)2]3+ and [Co(tme)2-(H2O)2]3+ complexes as catalysts: trien (diethylenetriamine) and tme (1,1,2,2-tetramethylethylenediamine). The acceleration is remarkable (10(8) to 10(9) fold), decreasing half-life of cAMP from 660,000 years to 7-15 hours. 相似文献
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A new assay for adenosine 3',5'-cyclic monophosphate in tissue 总被引:4,自引:0,他引:4
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Exercise-induced increases in myocardial adenosine 3',5'-cyclic monophosphate and phosphodiesterase activity 总被引:1,自引:0,他引:1
Numerous cellular biochemical events caused by hormones are mediated through cyclic AMP. Although many changes occur in the cell during exercise that could be attributed to this nucleotide, little evidence is available implicating it as an important regulator of exercise metabolism. In this investigation it was found that a 60 min bout of treadmill exercise caused a 2.4-fold increase in myocardial cyclic AMP immediately following the work. Rather than the immediate nucleotide hydrolysis that was expected, it was found that the elevated cyclic AMP level remained for approx. 24 h before returning to control levels. Cardiac glycogen fell to 30% of control after work but supercompensated 60% above control within 1 h following exercise. Therefore, cardiac cyclic AMP was elevated at a time when glycogen was being synthesized. Study of the temporal relationship between the exercise-induced increase in cyclic AMP and cyclic nucleotide phosphodiesterase indicated that the work caused an increase in the hearts' capacity to hydrolyze cyclic AMP. Measurement of heart phosphodiesterase at substrate concentrations of 1.0 and 100 microM produced significant increases in enzyme activity immediately following exercise which remained elevated for 48 h and was back to control activity 96 h following work. These data present a potentially fascinating model for the study of the dissociation between cyclic AMP, glycogenesis and elevations in phosphodiesterase activity in the heart. 相似文献
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H Kita R I Abu-Ghazaleh G J Gleich R T Abraham 《Journal of immunology (Baltimore, Md. : 1950)》1991,146(8):2712-2718
We have investigated the effects of cAMP on Ig-induced human eosinophil activation. Stimulation of human normodense eosinophils with IgG- or secretory IgA (sIgA)-coated Sepharose beads induced cellular degranulation, as measured by the release of the granule protein, eosinophil-derived neurotoxin (EDN). Pretreatment with cAMP analogs (N6,O2,-dibutyryl adenosine-3,':5' cyclic monophosphate; 8-bromoadenosine 3':5' cyclic monophosphate; or N6-benzoyladenosine 3':5' cyclic monophosphate) or cAMP phosphodiesterase-inhibitors (theophylline or isobutylmethyl xanthine (IBMX] strongly inhibited Ig-induced human eosinophil degranulation. The beta-adrenoceptor agonists, isoproterenol and salbutamol, induced relatively low level increases in intracellular cAMP, and weakly suppressed EDN release induced by IgG-coated beads. However, cellular pretreatment with IBMX synergistically enhanced the inhibitory effects of isoproterenol or salbutamol on both IgG and sIgA-induced eosinophil degranulation. Similarly, PGE2 treatment increased intracellular cAMP concentrations in eosinophils and correspondingly inhibited the Ig-dependent cellular degranulation response: co-incubation with IBMX further enhanced both effects of PGE2. Finally, cholera toxin, which irreversibly activates the stimulatory guanine nucleotide-binding protein linked to adenylyl cyclase, strongly inhibited the release of EDN from IgG- or sIgA-stimulated eosinophils. The time-dependent accumulation of cAMP in cholera toxin-treated cells closely paralleled the time courses of inhibition of IgG- and sIgA-induced EDN release after toxin exposure. These data indicate that the cAMP-dependent signal transduction mechanism in eosinophils exerts a negative modulatory effect on the cellular degranulation responses induced by sIgA or IgG. The inhibitory effects of cAMP on eosinophil activation may provide an important physiologic and a clinically relevant therapeutic mechanism for limiting the release of eosinophil-derived cytotoxic proteins during certain allergic or inflammatory responses in vivo. 相似文献
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The voltammetric oxidation of adenosine-3',5'-cyclic monophosphate (3',5'-CAMP) has been studied in the pH range 2.13-10.07 using pyrolytic graphite electrode (PGE). Voltammetric, coulometric, spectral studies, and product characterization indicate that the oxidation of 3',5'-CAMP occurs in an EC reaction involving a 6H+, 6e process at pH 7.24. Electrooxidized products were seperated by semipreparative high performance liquid chromatography (HPLC) and were characterized by mp, 1HNMR, FTIR, and GC-mass as allantoin cyclic ribose monophosphate and 3 dimers as the major products. A detailed interpretation of the redox mechanism of 3',5'-CAMP also has been presented to account for the formation of various products. 相似文献
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O. Kuchel F. H. Messerli G. Tolis P. Hamet J. Fraysse P. Cartier P. Roy R. Boucher J. Genest 《CMAJ》1977,116(9):992-996
The concentration of plasma adenosine 3'',5''-cyclic monophosphate (cyclic AMP) and plasma renin activity (PRA) were measured concomitantly in blood from both renal veins and in arterial blood in 22 hypertensive patients. In the nine patients with true renovascular hypertension the concentration of plasma cyclic AMP was greater in the venous effluent of the kidney affected by the renal artery stenosis than in that of the unaffected or less affected kidney. The arteriovenous difference in cyclic AMP concentration was less on the affected side in all but one patient. The arteriovenous differences in PRA identified the affected kidney as the source of hyper-reninemia and showed that renin release from the other kidney was suppressed. In the 13 patients with hypertension associated with but unrelated to renal artery stenosis there were no consistent patterns of cyclic AMP concentration or PRA in the venous effluent of the kidneys or of their arteriovenous differences. In renovascular hypertension the venous effluent of the kidney affected by renal artery stenosis contains not only more renin but also more cyclic AMP, owing to either increased cyclic AMP production or decreased excretion or extraction of cyclic AMP by the affected kidney. This unilateral increase in cyclic AMP concentration may become a complementary diagnostic feature of true renovascular hypertension. 相似文献
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K Masood V M Srivastava D P Singh R K Chatterjee A B Sen 《Journal of helminthology》1983,57(4):335-338
The filarial parasites Litomosoides carinii and Dipetalonema viteae both show transcuticular uptake of adenosine 3',5'-cyclic monophosphate but isoproterenol is taken up by D. viteae only. The importance of this difference is discussed from the point of view of metabolic regulation. Inhibition of uptake by lectins indicates the involvement of surface sugar moieties in the transport processes. 相似文献