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:4.6.1.1 (adenylate cyclase)
19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Isolated adrenal cells were obtained surgically from patients with primary aldosteronism, breast cancer, or Cushing's syndrome. They were prepared by the modification of Sayers method, and incubated at 37 degrees C for 2 hours under 95% O-2-5% CO-2, in the medium of calcium-free Krebs-Ringer bicarbonate buffer containing 0.2% glucose and 0.5% bovine serum albumin, to which various doses of calcium, ACTH, dibutyryl cyclic AMP or cycloheximide were added. Steroid production was measured by the method of Silber et al. In isolated normal adrenocortical cells, 11-OHCS was produced by calcium alone in the absence of ACTH or dibutyryl cyclic AMP, while it was not produced by ACTH alone without calcium. 11-OHCS production by ACTH was decreased in the high concentration of calcium (10.16 mM, 12.70 mM). Cycloheximide partially blocked an increase in 11-OHCS synthesis induced by calcium. These data suggest that adenyl cyclase of human adrenocortical cells may be stimulated by calcium alone, supporting the notion that calcium is a second messenger. The ratio of 11-OHCS production by calcium alone to that by dibutyryl cyclic AMP was higher in adenoma cells than in normal cells. This may account for the character of autonomic steroid production in adrenocortical adenoma cells.
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PMID:[Effect of calcium on steroidogenesis in isolated human adrenal cells (author's transl)]. 16

The present experiment was planned to verify the effect of calcium on adenyl cyclase in isolated human adrenal cells. Normal adrenal glands were obtained surgically from patients with primary aldosteronism and advanced breast cancer. Isolated adrenal cells were prepared by the modified Haning's method. They were incubated at 37C under a gas mixture of 95 percent O2: 5 percent CO2 in calcium-free Krebs-Ringer bicarbonate buffer solution containing 0.2 percent glucose and 0.5 percent fatty acid-free bovine serum albumin, to which various doses of CaCl2 or ACTH were added. Thirty minutes later, cyclic-AMP was measured by cyclic-AMP assay kit (The Radio-chemical Center, Amersham). 11-OHCS was estimated fluorometrically by the modified Silber's method after incubation for 2 hours. In the calcium-free incubation medium, productions of 11-OHCS and cyclic-AMP were negligible. In the concentration of 2.54 mM/L of calcium, 11-OHCS production increased with significant difference statistically, while the increase of cyclic-AMP production was not significant. In the concentration of 12.70 mM/L of calcium, however, cyclic-AMP production increased remarkably. When ACTH was added to the incubation medium containing 2.54 mM/L of calcium, productions of 11-OHCS and cyclic-AMP also increased remarkably. These results indicate that adenyl cyclase of human adrenocortical cells is directly stimulated by calcium and suggest that calcium acts as the second messenger of ACTH.
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PMID:[The effect of calcium on steroidogenesis in isolated human adrenal cells (author's transl)]. 20 11

Bilirubin (0.45 mM) inhibited lipolysis and stimulated [1-14C]glucose oxidation by rat fat cells in the presence of an equimolar concentration of bovine serum albumin. Bilirubin was an insulinlike agent with respect to inhibition of lipolysis and stimulation of glucose oxidation. There was a marked inhibition of adenylate cyclase activity of fat cell ghosts by 0.001--0.1 mM bilirubin in the absence of albumin, which was largely reversed by the addition of albumin. Although both bilirubin and free fatty acids bind to albumin, the primary binding sites appear to be separate. The effects of bilirubin at a molar ratio to albumin of 2 or less were not influenced by free fatty acid-to-albumin ratios up to 3. Triglyceride lipase activity of partially purified rat fat cell homogenates was inhibited by bilirubin in the presence of an equimolar concentration of bovine albumin. These data indicate that the antilipolytic action of bilirubin is probably due to direct inhibition of triglyceride lipase through a mechanism that does not involve competition with free fatty acids for binding to albumin.
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PMID:Effects of bilirubin on fat cell metabolism and lipolysis. 51 47

In the present study we investigated in vitro the effect of human serum albumin (HSA) on receptor-stimulated cAMP production in isolated human peripheral blood mononuclear cells (PBMC). The cAMP production is strongly correlated with the pH of the medium during long incubations with albumin. Adenylate cyclase is stimulated by receptor agonists like histamine, forskolin, prostaglandin E2 and the beta-adrenergic agonist isoprenaline, in the presence or absence of HSA. This protein, at concentrations above 0.1%, dose-dependently inhibits both basal and agonist-stimulated cAMP levels in PBMC. In the presence of 0.5% HSA a significant reduction of 30-60% (cell batch dependent) is induced, a reduction which is not incubation time dependent. Washing the cells after a period of incubation with 2% HSA does not reverse the HSA-induced cAMP inhibition. Oleic acid-evoked conformational changes in HSA were not capable of influencing the inhibition processes of HSA on the isoprenaline-stimulated cAMP production. Structure-controlled interactions between HSA and membrane or adenylate cyclase are therefore unlikely. Bovine serum albumin and chicken albumin had different effects upon the agonist-stimulated cAMP production as compared with HSA. At this moment no explanation for this behavior can be provided. The findings indicate that albumin may inhibit non-specifically cAMP production in PBMC and possibly influences membrane-controlled processes.
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PMID:Effect of albumin on adenylate cyclase receptor-related signal transduction of human peripheral blood mononuclear cells. 137 27

We hypothesized that Iloprost, a long-acting prostacyclin analog, would inhibit neutrophil (PMN)-induced lung injury and decrease PMN adherence to vascular endothelium. Human PMNs infused into isolated buffer-perfused rat lungs subsequently stimulated with phorbol myristate acetate (PMA) resulted in lung injury as assessed by the accumulation of [125I]bovine serum albumin (125I-BSA) in lung parenchyma and alveolar lavage fluid. Addition of Iloprost to the lung perfusate, prior to activation of the PMNs, reduced lung injury as assessed by a decrease in the accumulation of 125I-BSA in the lung. This protective effect was not due to the vasodilatory effect of Iloprost. Protection by Iloprost was not linked to a reduction in PMA-induced PMN superoxide production since Iloprost did not reduce the amount of superoxide released into lung perfusate. In vitro, Iloprost caused a dose-dependent inhibition of PMA-stimulated PMN adherence to endothelial cells. Iloprost did not affect the number of Mo1 adhesion molecules constitutively expressed or the number of receptors expressed on the PMNs following PMA. Addition of cAMP or dibutyryl cAMP to the endothelial cells mimicked the effects of Iloprost, diminishing PMA-stimulated PMN adhesion. In separate experiments, addition of the phosphodiesterase inhibitor IBMX to Iloprost resulted in a greater inhibition of PMA-stimulated PMN adherence, while addition of an adenylate cyclase inhibitor, SQ 22,536, or cAMP antibodies with the Iloprost abolished Iloprost's inhibitory effect on PMN adhesion. Thus, Iloprost inhibits PMA-activated PMN-induced lung injury despite continued superoxide production. Iloprost inhibition of PMN adhesion is dependent on cAMP.
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PMID:Iloprost inhibits neutrophil-induced lung injury and neutrophil adherence to endothelial monolayers. 169 99

Histamine H2 receptor (H2R) has been shown to be coupled to adenylate cyclase. However, we have previously demonstrated that H2R-specific stimulation also activated phospholipase C in human HL-60 promyelocytic leukemia cells (Mitsuhashi M. et al. J. Biol. Chem. 264:18356, 1989). We have extended these studies on HL-60 cells to investigate whether histamine-bovine serum albumin conjugates (HA-BSA) specifically recognize H2R and activate phospholipase C pathways. Both histamine (HA) and HA-BSA increased intracellular concentrations of calcium in a H2R specific manner. However, HA-induced calcium mobilization was transient and returned to the basal level within 1-2 min, whereas HA-BSA-induced calcium mobilization was sustained for more than 10 min as a result of the additional influx of extracellular calcium. More interestingly, fluorescein (FITC) labeled HA-BSA was less incorporated into cytosols and present in the membrane fractions for more than 60 min, whereas membrane-bound FITC-HA was rapidly incorporated into cytosols. Furthermore, the levels of inositol 1,3,4,5-tetrakisphosphate, which is known to activate calcium channels were more sustained after HA-BSA stimulation than those of HA alone. These data suggest that H2R activation mechanism is more complex and may be modified by this slowly metabolized "compound ligand".
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PMID:Multiple signaling pathways of histamine H2 receptors. 190 5

Epithelial cells isolated from fragments of hamster pancreas interlobular ducts were freed of fibroblast contamination by plating them on air-dried collagen, maintaining them in serum-free Dulbecco's modified Eagle's (DME):F12 medium supplemented with growth factors, and selecting fibroblast-free aggregates of duct cells with cloning cylinders. Duct epithelial cells plated on rat type I collagen gel and maintained in DME:F12 supplemented with Nu Serum IV, bovine pituitary extract, epidermal growth factor, 3,3',5-triiodothyronine, dexamethasone, and insulin, transferrin, selenium, and linoleic acid conjugated to bovine serum albumin (ITS+), showed optimal growth as monolayers with a doubling time of about 20 h and were propagated for as long as 26 wk. Early passage cells consisted of cuboidal cells with microvilli on their apical surface, complex basolateral membranes, numerous elongated mitochondria, and both free and membrane-bound ribosomes. Cells grown as monolayers for 3 mo. were more flattened and contained fewer apical microvilli, mitochondria, and profiles of rough surfaced endoplasmic reticulum; in addition, there were numerous autophagic vacuoles. Functional characteristics of differentiated pancreatic duct cells which were maintained during extended monolayer culture included intracellular levels of carbonic anhydrase and their capacity to generate cyclic AMP (cAMP) after stimulation by 1 X 10(-6) M secretin. From 5 to 7 wk in culture, levels of carbonic anhydrase remained stable but after 25 to 26 wk decreased by 1.9-fold. At 5 to 7 wk of culture, cyclic AMP increased 8.7-fold over basal levels after secretin stimulation. Although pancreatic duct cells cultured for 25 to 26 wk showed lower basal levels of cAMP, they were still capable of generating significant levels of cAMP after exposure to secretin with a 7.0-fold increase, indicating that secretin receptors and the adenyl cyclase system were both present and functional. These experiments document that pancreatic duct monolayer cultures can be maintained in a differentiated state for up to 6 mo. and suggest that this culture system may be useful for in vitro physiologic and pathologic studies.
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PMID:Characterization of differentiated Syrian golden hamster pancreatic duct cells maintained in extended monolayer culture. 212 5

We examined the effects of cationized serum albumin on the canine renal membrane adenylate cyclase in the basal state and when stimulated with guanylyl-imidodiphosphate, PTH or NaF. Human albumin was cationized to an isoelectric point greater than 9.5 by the addition of hexamethylene diamine. Cationized albumin increased basal and stimulated cAMP production by the membranes and increased the sensitivity of the system to low doses of PTH (0.25 pmol/l), being usually inactive in buffer alone or in human serum albumin. These observations are comparable to those previously reported on thyroid membranes and cells from adrenal tumours and confirm that positively charged macromolecules can increase adenylate cyclase activity. A decrease in non-specific binding of PTH is only partly responsible for the increased sensitivity to the hormone. Though this increase in sensitivity is small, it could nevertheless be useful in the detection of biologically active PTH after extraction from the serum.
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PMID:Cationized serum albumin enhances basal and stimulated adenylate cyclase activity in canine renal membranes. 282 22

Very little has been known of the biochemical function of a human adrenocortical carcinoma cell line, SW-13. In this study, the production of several adrenal steroids and 3', 5'-cyclic adenosine monophosphate (cAMP) were investigated in this cell line. The cells were incubated in L-15 medium containing 0.1% bovine serum albumin with several reagents in an atmosphere of 5% CO2 and 95% air for 2 hours at 37 degrees C. Aldosterone (Ald), corticosterone (B), cortisol (F), dehydroepiandrosterone sulfate (DHEA-S) and cAMP were simultaneously assayed by specific radioimmunoassays in the medium and cells. Significant increases in cAMP production were observed by cholera toxin (10 ng/ml) and forskolin (10 nM), both direct stimulators of adenylate cyclase, in the cAMP concentration without an increase in the steroids. The DHEA-S concentration in the medium was significantly increased by angiotensin-II (10(-7)M), noradrenalin (3 X 10(-5) M), adrenalin (3 X 10(-5) M) or alpha-melanocyte-stimulating hormone (alpha-MSH, 10(-7) M), none of which was associated with cAMP production. Neither adrenocorticotropin (10(-10) M) nor human chorionic gonadotropin (500 mIU/ml) stimulated the release of the steroids or cAMP production. A calcium ionophore, A23187 (10(-7) M), and 12-O-tetradecanoylphorbol-13-acetate (10(-8) M), a direct stimulator of protein kinase C, stimulated the release of DHEA-S, but not those of Ald, B and F. The results suggest that SW-13 retains functioning adenylate cyclase which, however, is not linked with steroidogenesis and that DHEA-S is produced probably by the mechanisms which involve protein kinase C system or calcium ion. This report provides the first demonstration of cAMP and DHEA-S production in SW-13 and suggests that this cell line is potentially useful for investigating the mechanisms of steroidogenesis in the human adrenal cortex.
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PMID:Dehydroepiandrosterone sulfate (DHEA-S) and 3', 5'-cyclic adenosine monophosphate (cAMP) production in a cultured human adrenocortical carcinoma cell line (SW-13). 284 Feb 74

A mouse model for pertussis immunization encephalopathy has been described with features that closely resemble the severe adverse reactions occasionally seen after pertussis vaccine administration,m including seizures and a shock-like state leading to death. These reactions are produced with nearly one hundred percent efficiency provided that the mice immunized with Bordetella pertussis have 1) the appropriate major histocompatibility (H-2) genotype, 2) have been sensitized to bovine serum albumin (BSA), and 3) that the injected B. pertussis contained sufficient amounts of pertussis toxin. Antibody titres were measured in mice with haplotypes H-2d.s.k. that are highly susceptible to encephalopathy as well as in H-2b mice, that are totally resistant. Mice with H-2d.s.k. haplotypes were high responders to BSA, while H-2b (B10) mice were non-responders to BSA. Both H-2d and H-2b mice responded well to B. pertussis. Encephalopathy was induced in resistant H-2b mice with B. pertussis and passively administered anti-BSA antiserum, but not with B. pertussis and anti-(T,G)-A--L antibody. This indicated that B. pertussis and anti-BSA were absolutely required for development of encephalopathy. Encephalopathy could be induced in mice decomplemented with cobra venom factor and given BSA and B. pertussis. Several single-site mutants of B. pertussis affecting single virulence factors were induced with transposon Tn5. One of these mutants, BP357, deficient in pertussis toxin production, had a greatly reduced encephalopathic potential in the mouse model compared to the virulent strain BP 338, or to BP348, an adenylate cyclase and hemolysin double mutant, or to BP 349, a hemolysin mutant.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Murine model for pertussis vaccine encephalopathy: role of the major histocompatibility complex; antibody to albumin and to Bordetella pertussis and pertussis toxin. 287 26


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