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

---

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

Among opiatelike peptides, stimulatory as well as inhibitory effects are encountered on adenylate cyclase activity. These actions are dependent not only on the investigated brain region but also on the applied peptide. Met-enkephalin stimulates adenylate cyclase activity in the rat brain stem (D-Met2, Pro5)-enkephalinamide and beta-endorphin inhibited it, whereas all three peptides inhibited the activity of cortex. Naloxone antagonized the effects of the applied peptides in the presence of sodium chloride.
...
PMID:Effect of Met-enkephalin and (D-Met2,Pro5)-enkephalinamide on the adenylate cyclase activity of rat brain. 49 49

In cholera, bacteria proliferation in the lumen of the small bowel results in an increase in adenylate cyclase activity and concentration of adenosine 3',5'-cyclic monophosphate (cAMP). Clinical manifestations of cholera can be attributed to the change in cAMP synthesis. Accumulation of cAMP in intestinal epithelial cells lead to the development of 2 separate alterations of active ion transport, both of which contribute to the overall rate of secretion of salt and water. Inhibition of sodium chloride absorption occurs in villus cells, while stimulation of active secretion of anion (chloride and bicarbonate) occurs in secretory cells. Glucose is useful in reinstituting salt and H2O absorption as it does not interfere with the specific effects of cAMP on active ion transport but independently stimulates salt and H2O absorption. If enough of sodium-glucose solution is given, fecal losses can be fully replaced and fluid balance maintained. However, an oral glucose electrolyte therapy does not decrease diarrhea, and it is important to design an oral solution that could stimulate extra fluid absorption. Oral sugar-electrolyte solutions are used world wide to treat diarrhea of diverse and often undetermined causes; theoretically, they should be useful for replacing fluid losses in any form of diarrhea, infectious or noninfectious, as long as the intestine can absorb the ingested glucose. Palmer proposed an interesting variation on the glucose theme by using sucrose. Although oral sugar-electrolyte therapy has proved to be successful, innovations are still needed.
...
PMID:New strategies for treating watery diarrhea. 90 68

The effects of an adenosine analog, N6-phenyl-isopropyl-adenosine (PIA), on the glucagon-stimulated adenylate cyclase activity in rat hepatic membranes were studied. Adenosine at high concentrations (greater than 10 microM) has been reported exclusively to inhibit the adenylate cyclase via intracellular P-sites of the hepatic membrane. The stimulation by glucagon of the enzyme was attenuated by nanomolar concentrations of PIA in the presence of low concentrations (less than 1.0 microM) of GTP, indicating the effect of the guanine nucleotide inhibitory system (Ni). This inhibition by PIA required the presence of sodium chloride and was antagonized with isobutyl methylxanthine, an antagonist for the extracellular R-site receptors. The inhibitory effects of PIA disappeared and reversed into a stimulatory phase with increasing concentrations of GTP, suggesting the presence of a stimulatory (Ns) and an inhibitory (Ni) guanine nucleotide system of the enzyme in the action of the adenosine. PIA concentrations over a micromolar were observed to stimulate the enzyme activity in a GTP-dependent manner, indicating the presence of the stimulatory receptor (A2 or Ra) coupled to the Ns. These results suggest that receptors for adenosine of the inhibitory type (A1 or Ri) and the stimulatory type (A2 or Ra) are present on the rat hepatic membrane, showing multiple controls of the adenylate cyclase system, depending on the cellular concentrations of GTP and/or sodium chloride.
...
PMID:Multiple controls by adenosine receptors on the adenylate cyclase in the rat hepatic membrane. 169 17

The effects of the adenosine receptor agonists (-)-N6-phenylisopropyladenosine (PIA) and 5'-N-ethylcarboxamideadenosine (NECA) on the force of contraction, adenylate cyclase activity and cAMP content in the presence of isoprenaline (Iso) were studied in ventricular preparations of the guinea-pig heart. Only in the presence of adenosine deaminase (ADA) and 50 mM sodium chloride, i.e. under 'optimal' conditions, did PIA and NECA reduce the Iso-stimulated adenylate cyclase activity in broken cell preparations, with a maximal effect of about 25%. In electrically driven (1 Hz) papillary muscles from guinea-pigs, both compounds concentration dependently reduced the Iso-stimulated force of contraction maximally by about 50% in the presence of ADA (1 microgram/ml). cAMP was measured in the same preparations. Low concentrations (0.1-1 microM) of PIA reduced the cyclic AMP content while higher concentrations increased the cyclic AMP content. The negative inotropic effect of NECA was accompanied by a concentration-dependent increase in the cyclic AMP content. We conclude that the negative inotropic effect of PIA in the presence of Iso is only in part due to a decrease in the cyclic AMP content resulting from inhibition of adenylate cyclase activity. Such an effect was only detected in the presence of ADA so that endogenous adenosine can obviously mask small effects of PIA on adenylate cyclase activity or the cyclic AMP content. In addition, the negative inotropic effect of NECA in the presence of isoprenaline was not accompanied by a reduction but an increase in the cyclic AMP content.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Effects of adenosine analogues on force and cAMP in the heart. Influence of adenosine deaminase. 254 33

We have attempted to clarify the mechanism whereby the sensitivity to detect thyroid stimulating antibodies by use of cultured thyroid cells is enhanced when sodium chloride is removed from isotonic medium. Preexposure of cultured porcine thyroid cells to 10(-4) mol/l cycloheximide increased the subsequent cAMP response to TSab stimulation in isotonic NaCl medium, but not in hypotonic NaCl-free medium. Crude membrane fractions from porcine thyroid tissues were incubated with 6 Graves' IgGs in NaCl or NaCl-free medium at 37 degrees C for 1 h, centrifuged, washed, added [125I]TSH, and incubated for another hour. The result of the 'residual TBII assay' indicated that all 6 IgGs exhibited greater inhibition of [125I]TSH binding to the membranes when pre-incubated under hypotonic than isotonic conditions. When cultured porcine thyroid cells were incubated with 7 TSab samples in NaCl or NaCl-free medium depleted with 3-isobutyl-1-methylxanthine at 37 degrees C for 1 h, washed, added the NaCl-free medium containing 3-isobutyl-1-methylxanthine, and incubated for another 2 h, the use of NaCl-free medium during the pre-incubation resulted in greater increase in cAMP elicited by all 7 samples. In summary, 1) an inhibitory mechanism upon adenylate cyclase seems to be involved under isotonic conditions and may require new protein synthesis; 2) the binding of TSH receptor antibodies to the TSH receptor increases when NaCl is removed from isotonic medium, and 3) these factors are considered responsible for the enhanced sensitivity under hypotonic conditions.
...
PMID:Mechanisms of increased sensitivity for detection of thyroid stimulating antibodies by use of hypotonic medium. 257 Apr 97

Theophylline inhibits basal adenylate cyclase activity as well as cyclase stimulated by sodium chloride, sodium fluoride, GTP or 5'-guanylimidodiphosphate. This inhibition, is dose-dependent and shows non-competitive inhibition, with respect to MgATP. The presence of adenosine deaminase does not alter the effect of theophylline. The inhibition produced by theophylline is not additive with that due to 2'-deoxyadenosine 3'-monophosphate (a P-site agonist). It is suggested that theophylline may act at the P-site to reduce adenylate cyclase activity.
...
PMID:Inhibition of rabbit cardiac adenylate cyclase by theophylline. 286 8

The activity of adenylate cyclase in striatal membrane-enriched fractions (25,000 g) was inhibited by morphine, beta-endorphin, [D-Ala2-D-Leu5] enkephalin (DADLenk), fentanyl and bremazocine. Whereas guanosine triphosphate (GTP) appeared essential for the expression of this effect, sodium chloride seemed to enhance the degree of inhibition. Dopamine stimulation and sodium fluoride activation of the enzyme was also suppressed by morphine, beta-endorphin and DADLenk. beta-Endorphin and DADLenk inhibited adenylate cyclase activity in vasa deferentia membrane-enriched fractions (25,000 g); both opioids required GTP and NaCl and were inhibited by a delta-opioid receptor antagonist and by naloxone. Morphine, bremazocine and tifluadom did not significantly alter the activity of the vas deferens enzyme. Basal cyclic AMP values of striatal slices were not significantly altered by morphine, beta-endorphin or DADLenk. However, dopamine-induced elevation of cyclic AMP was reduced by morphine and this effect of the opiate was suppressed by naloxone. Only beta-endorphin lowered the basal cyclic AMP values in the vas deferens. The physiological relevance of adenylate cyclase coupling to opioid receptor subtypes is considered.
...
PMID:Opioid inhibition of adenylate cyclase in the striatum and vas deferens of the rat. 302 42

The effects of magnesium and sodium ions on adenylate cyclase activity in plasma membranes from chicken heart and eggshell gland mucosa were studied. It was found that the increase in magnesium chloride concentration from 5 to 40 mM results in the stimulation (4.1-fold) of the adenylate cyclase activity. The increase in sodium chloride concentration up to 150 mM stimulated the enzyme activity 2-fold. The stimulation of adenylate cyclase by magnesium and sodium ions was less pronounced in the eggshell gland. GTP did not activate adenylate cyclase. The activating effect of magnesium and sodium ions was accompanied by the attenuation of the enzyme sensitivity to NaF, guanylyl imidodiphosphate and isoproterenol. Activation by guanylyl imidodiphosphate was completely abolished in the presence of 40 mM magnesium chloride. It is assumed that high concentrations of the salt promote subunit dissociation of the adenylate cyclase regulatory protein and its interaction with the catalytic subunit in the presence of endogenous nucleotides. The differences in the adenylate cyclase sensitivity to cations in chicken heart and eggshell gland mucosa correlate with the amount of pertussis toxin substrate.
...
PMID:[Regulation by cations of adenylate cyclase activity in chicken tissues]. 317 68

Tumors associated with humoral hypercalcemia of malignancy (HHM) contain parathyroid hormone-like adenylate cyclase-stimulating proteins (hACSPs). We previously purified a 17,000 MW hACSP from an HHM-associated breast carcinoma. This report describes the characterization of hACSPs from three additional HHM-associated tumors: two typical HHM-associated tumors (squamous carcinomas) and a third unusual tumor type (pheochromocytoma). Each tumor was extracted in acid-urea/ethanol-sodium chloride, and adenylate cyclase-stimulating activity (ACSA) was examined following reverse-phase and size-exclusion HPLC and isoelectric focusing. Each tumor contained a high molecular weight form of ACSA which co-eluted with the 17,000 molecular weight breast carcinoma hACSP in each of the three separation procedures. Each also contained a lower molecular weight form(s) of ACSA (6,000-9,000 molecular weight). Both forms were inhibited by Nle8,18Tyr34bPTH(3-34) amide. The high molecular weight form was not changed to the lower molecular weight form by a reducing agent. Some HHM-associated tumors contain two forms of hACSP, one with a molecular weight of 17,000 and another with a molecular weight of 6,000-9,000, which appears to be an amino-terminal cleavage product of the larger protein.
...
PMID:Two forms of parathyroid hormone-like adenylate cyclase-stimulating protein derived from tumors associated with humoral hypercalcemia of malignancy. 345 36

The effect of drastic sodium chloride changes (performed by using low-Na diet + furanthril and high-Na diet) on renin-angiotensin-aldosterone system, vasopressin and renal prostaglandins was studied in normal subjects after inhibition of prostaglandin synthesis by indomethacin (0.35 mg/kg three times daily for 13 days). The purpose of the investigation was to evaluate the mechanism of prostaglandin-vasopressin interrelationship. Indomethacin inhibition of PG-synthesis was performed, and after high-Na provocation, an increase of vasopressin and cyclic AMP excretion by 15% and 376% more than that without indomethacin was found. Indomethacin by itself caused sodium retention and antidiuretic effect. The results confirmed the assumption that renal prostaglandins are modulators of renin release from the kidney and that they alternate vasopressin effect on urine concentration, most probably through adenylate cyclase-cAMP system.
...
PMID:Humoral factors involved in the regulation of sodium-fluid balance in normal man. II. Effect of indomethacin on sodium concentration, renal prostaglandins, vasopressin and renin-angiotensin-aldosterone system. 609 12


1 2 3 Next >>

---