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1.
When guanosine 3',5'-monophosphate (cyclic GMP) and adenosine 3',5'-monophosphate (cyclic AMP) are localized in canine thyroid by a flurescence Immunocytochemical procedure, distinct staining patterns for each nucleotide are seen: Cyclic AMP is distributed throughout the follicular cell cytoplasm before and after administration of thyroid-stimulating hormone, while cyclic GMP is localized to the follicular cell mumbrane in the control state, and increased cytoplasmic fluorescence is visualized after acetylcholine. These data provide histological evidence that correlates with cyclic nucleotide tissue measurements, sugesting diverse roles of the two nucleotides in thyroid function.  相似文献   

2.
The distribution of adenosine 3',5'-monophosphate (cyclic AMP) in fields of aggregating amoebae of Dictyostelium discoideum was examined by a novel isotope dilution-fluorographic technique. Cellular cyclic AMP was visualized by its competition with exogenous 3H-labeled cyclic AMP for high-affinity binding sites on protein kinase immobilized on a Millipore filter used to blot the monolayer. The cyclic AMP was distributed in spiral or concentric circular wave patterns which centered on the foci of the aggregations. These patterns were correlated with those of cell shape change that propagate through the monolayers: cells in regions of high concentrations of cyclic AMP were elongated (presumably moving up a cyclic AMP gradient), whereas those in regions of low cyclic AMP concentrations were randomly directed. The highest cyclic AMP concentrations were about 10(-6)M. The widths of the regions of elevated cyclic AMP were about 0.3 to 1 millimeter which, assuming a wave velocity of 300 micrometers per minute, suggests that a cell signals for about 1 to 3 minutes. These observations support the hypothesis that the aggregation process in Dictyostelium is mediated by the periodic relay of cyclic AMP signals and suggest a simple scheme for the dynamics of the aggregation process.  相似文献   

3.
Human neutrophilic leukocytes release neutral protease and beta-glucuronidase during cell contact with, and phagocytosis of, zymosan particles treated with rheumatoid arthritic serum. Release of lysosomal enzymes is inhibited by epinephrine and adenosine 3',5'-monophosphate (cyclic AMP), but not by phenylephrine or adenosine 5'-monophosphate. Inhibition of enzyme release by epinephrine may be mediated by cyclic AMP because the cyclic AMP in the neutrophils is increased by epinephrine treatment at the time when enzyme release is reduced.  相似文献   

4.
Adenosine 3'5'-monophosphate: inhibition of complement-mediated cell lysis   总被引：2，自引：0，他引：2  
An increase in adenosine 3',5'-monophosphate (cyclic AMP) in rat mast cells, achieved by stimulating the cells with prostaglandin E(1), by preventing cyclic AMP breakdown with aminophylline, or by adding exogenous dibutyryl cyclic AMP, prevented complement-mediated cytolysis as assessed by both histamine release and vital dye exclusion. Dibutyryl cyclic AMP also suppressed water-induced osmotic lysis.  相似文献   

5.
Histone phosphorylation: stimulation by adenosine 3',5'-monophosphate   总被引：27，自引：0，他引：27  
Adenosine cyclic 3',5'-monophosphate at a concentration of 10-(7)M causes a four-to sixfold increase in the rate of histone phosphorylation catalyzed by a liver enzyme preparation. This observation suggests a mechanism for the induction of RNA synthesis by those hormones that cause increases in the concentration of cyclic AMP.  相似文献   

6.
A biologically active rhodamine conjugate of thyrotropin binds at 4 degrees C to diffusely distributed membrane thyrotropin receptors which patch and become endocytosed into thyroid cells in a temperature-sensitive process. When the cells are first incubated with 8-bromo-cyclic adenosine monophosphate at 37 degrees C, the conjugate also binds to clustered receptors at 4 degrees C. Furthermore, 8-bromo-cyclic adenosine monophosphate reduces the amount of adenosine 3',5'-monophosphate (cyclic AMP) induced by thyrotropin. Hence, increased intracellular cyclic AMP induces receptor patching and reduces the concentration of cyclic AMP normally induced by thyrotropin. This suggests that cyclic AMP acts both as the second messenger of thyrotropin and also as the regulator of the level of thyrotropin receptors.  相似文献   

7.
M Knecht  K J Catt 《Science (New York, N.Y.)》1981,214(4527):1346-1348
The antigonadal effects of gonadotropin-releasing hormone in ovarian granulosa cells are due to attenuation of the adenosine 3',5'-monophosphate (cyclic AMP) response to follicle-stimulating hormone. Agonists of gonadotropin-releasing hormone progressively inhibit adenylate cyclase and stimulate phosphodiesterase activities in cultured granulosa cells, indicating that blockade of gonadotropin action is attributable to the combined effects of decreased production and increased degradation of cyclic AMP.  相似文献   

8.
Low concentrations (10(-9)M) of 5-hydroxytryptamine increase the rate of fluid secretion by isolated salivary glands of adult Calliphora. 5-Hydroxytry ptamine is present in Calliphora brain. Adenosine-3',5'-monophosphate (cyclic AMP) also stimulates fluid secretion and may be involved in the mode of action of 5-hydroxytryptamine.  相似文献   

9.
Two positional isomers (9 and 11) of trans octadecenoates did not support growth on glucose of an Escherichia coli mutant that requires unsaturated fatty acids. However, the trans fatty acids provided sufficient fluidity to produce much higher cell yields when the concentration of adenosine 3',5'-monophosphate was raised. The effectiveness of the trans acids rose from 0 to 1 cell per femtomole to 15 to 20 cells per femtomole as the concentration of adenosine 3',5'-monophosphate was increased. The corresponding cis positional isomers supported high yields (35 to 40 cells per femtomole) independent of supplementation. The enhanced growth with adenosine 3',5'-monophosphate supplementation is not due to an increased uptake and incorporation of the trans isomers relative to the cis isomers, since the 9-trans isomer was incorporated more rapidly than the 9-cis isomer into the membrane phospholipids under all growth conditions and represented 21 +/- 2 mole percent of the acids. The finding that cells growing with trans fatty acid isomers have a higher requirement for adenosine 3',5'-monophosphate may indicate that some fatty acids can alter the metabolic regulation normally exerted by the cyclic nucleotide.  相似文献   

10.
Protein kinase was partially purified from Chang's liver cells, 3T6 mouse embryo fibroblasts, and HeLa cells. The rate of histone phosphorylation catalyzed by the kinase from each of these cell lines was stimulated two- to three-fold by 1 x 10(-6) molar adenosine 3',5'-monophosphate. The same concentration of guanosine 3',5'-monophosphate failed to stimulate these kinases.  相似文献   

11.
Inhibition of cell growth in vitro by adenosine 3',5'-monophosphate   总被引：18，自引：0，他引：18  
Adenosine 3',5'-monophosphate, at a concentration of 40 micrograms per milliliter, inhibits the growth of HeLa and strain L cells in culture. The inhibition becomes progressively greater during the incubation of the cells. Adenosine 5'-monophosphate and adenosine, metabolites of adenosine 3',5'-monophosphate, do not affect the growth of either cell culture. This suggests that 3',5'-monophosphate enters the cell without alteration. Dibutyryl-adenosine 3',5'-monophosphate, reported to have a greater activity than adenosine 3'5'-monophosphate on several tissues, inhibited the growth of the cells much less.  相似文献   

12.
Thyroid-stimulating hormone increased the cyclic 3',5'-adenosine monophosphate concentration in dog thyroid slices during a 1-minute incubation period and produced a maximum effect soon thereafter. The elevation persisted for at least 30 minutes. The concentrations of the cyclic 3',5'-adenosine monophosphate increased as the TSH concentration was increased from 0.125 to 50 milliunits per milliliter. Prostaglandin E(1), which increases glucose oxidation in dog thyroid slices, also increased the concentration of cyclic 3',5'-adenosine monophosphate. Although sodium fluoride stimulates thyroid adenyl cyclase, it did not increase concentration of cyclic 3',5'-adenosine monophosphate. Carbamylcholine and menadiol sodium diphosphate augment glucose oxidation in dog thyroid slices but do not change concentrations of cyclic 3',5'-adenosine monophosphate.  相似文献   

13.
The crystal structure of the triethylammonium salt of cyclic uridine-3',5'-phosphate was solved by use of the tangent formula to refine phase angles based upon the positions of six of the atoms. The two independent uracil rings are planar and in the keto form. The base-sugar torsion angles are in the anti range. The sugar puckering is C3'-endo, and the ribose conformation about the C5'-C4' bond is transgauche.  相似文献   

14.
The importance of adenyl cyclase and adenosine 3',5'-monophosphate in the induction of tyrosine aminotransferase by adrenocorticosteroids has been tested in HTC cells derived from a rat hepatoma and grown in tissue culture. Adrenocorticosteroids cause a 10-to 15-fold increase in the rate of synthesis of tyrosine aminotransferase in these cells. Under various experimental conditions, with or without glucocorticoids, neither adenyl cyclase nor cyclic adenosine mono-phosphate could be detected in HTC cells. In addition, neither the cyclic nucleotide nor N(6), O(2')-dibutyryl cyclic adenosine monophosphate caused increased activity of the transaminase in HTC cells. We conclude that induction of tyrosine aminotransferase by glucocorticoids is not mediated by the adenyl cyclase-cyclic adenosine monophosphate system.  相似文献   

15.
The growth in vitro of human breast cancer cells, line MCF-7, was inhibited by a daily supplement of L-arginine (1 milligram per milliliter). Arginine acted synergistically with dibutyryl adenosine 3',5'-monophosphate (cyclic AMP) (10(-6) molar) to enhance the growth inhibitory effect: the cell replication ceased completely within 2 days after treatment. The growth arrest accompanied a change in cell morphology and was preceded by increases in the cellular concentration of cyclic AMP, adenylate cyclase, and type II cyclic AMP-dependent protein kinase activities as well as a decrease of estrogen binding activity. The results suggest that growth of human breast cancer cells is subject to cyclic AMP-mediated regulation and that arginine may play a specific role in this process.  相似文献   

16.
Immunocytochemistry shows that early during phagocytosis of zymosan, adenosine 3',5'-monophosphate (cyclic AMP) appears on the cell surface before the phagosome is internalized. The appearance of cyclic AMP on the cell surface is coincident with that of granule products and regulatory subunit of type I cyclic AMP-dependent protein kinase. Guanosine 3',5'-monophosphate is not associated with the initiation site of phagocytosis, but is observed throughout the granular cytoplasmic region. This sharply localized accumulation of cyclic AMP may serve as a signal for the initiation of phagocytosis.  相似文献   

17.
The acellular slime mold Physarum polycephalum releases a soluble adenosine 3', 5'-monophosphate phosphodiesterase into the growth medium. Although this enzyme resembles the particulate diesterase of the same organism in kinetic properties and in inhibition by methyl purines, its greater stability, its insensitivity to stimulation by imidazole and to inhibition by adenosine triphosphate,- and its selective release into the medium indicate a specific function, perhaps protection against exogenous cyclic nucleotide, for the soluble enzyme.  相似文献   

18.
Brief stimulation of cholinergic preganglionic nerve fibers resulted in an increase in guanosine 3',5'-monophosphate (cyclic GMP) in the bullfrog sympathetic ganglion. When the release of synaptic transmitter was prevented by a high-magnesium, low-calcium Ringer solution, stimulation of preganglionic nerve fibers did not increase cyclic GMP in the ganglion. The increase in cyclic GMP caused by preganglionic stimulation was also blocked by the muscarinic antagonist, atropine. The data indicate that the increase in cyclic GMP is associated with synaptic transmission and support the possibility that cyclic GMP may mediate the postsynaptic action of acetylcholine at muscarinic cholinergic synapses.  相似文献   

19.
The distribution of cyclic 3',5'-nucleotide phosphodiesterase activity in rat cerebral cortex was determined by cytochemical methods. The detectable phosphodiesterase activity was localized in postsynaptic (dendritic) nerve endings, most of it immediately adjacent to the synaptic membrane. Most of the postsynaptic nerve endings showed phosphodiesterase activity.  相似文献   

20.
An enzyme that hydrolyzes cyclic ',5'-adenosine monophosphate to 5'-adenosine monophosphate was found in the culture medium of the cellular slime mold Dictyostelium discoidum. The enzymatic activity shows a pH optimum of 7.5, and magnesium is required for maximum activity. The enzyme is not inhibited by caffeine. It has a Michaelis-Menten constant of 2 x 10(-3)M and its molecular weight is around 300,000.  相似文献   

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