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)

This study examine the regulation Na+, K(+)-ATPase activity in the medullary thick ascending limb of Henle Na+, K(+)-ATPase activity was determined in medullary thick ascending limb of Henle (mtal) segments dissected from rat kidneys. The sodium concentration in the medium (Nam) was 20 or 70 mM. Since the segments were permeabilized, intracellular Na+ (Nai) was assumed to be the same as Nam. Dibuturyl cyclic adenosine monophosphate (dbcAMP) and forskolin inhibited Na+, K(+)-ATPase activity independently of Nam. Arginine vasopressin (AVP) receptors coupled to adenylate cyclase have been identified in the medullary thick ascending limb of Henle. At Nam = 20 mMAVP caused a dose-dependent inhibition of Na+, K(+)-ATPase activity with a maximal effect (49%) at 10(-8) M. This inhibition was abolished in the presence of the adenylate cyclase inhibitor 2,5-dideoxyadenosine (2, 5-DDA). AVP had no effect on Na+, K(+)-ATPase activity in the mTAL at Nam = 70 mM. The guanosine-diphosphate analogue GDP beta S inhibited Na+, K(+)-ATPase activity at Nam = 70 mM but not at Nam = 20 mM. We conclude that increased cyclic adenosine monophosphate (cAMP) levels inhibit Na+, K(+)-ATPase activity in mTAL. AVP can, depending on Nai, produce this effect by adenylate cyclase activation. The guanonine nucleotide binding protein G-protein might be the site of Na(+)-dependence.
...
PMID:Sodium-dependent regulation of sodium, potassium-adenosine-tri-phosphatase (Na+, K(+)-ATPase) activity in medullary thick ascending limb of Henle segments. Effect of cyclic-adenosine-monophosphate guanosine-nucleotide-binding-protein activity and arginine vasopressin. 131 76

Patterns of in vitro renal renin release and the ability of atriopeptin to directly inhibit renin release have been examined in the rat, rabbit, and dog, but have been unstudied in the primate kidney. Accordingly, we examined renin release from superficial renal cortical slices of the squirrel monkey (Samiri sciuresus). The average age of the 5 animals was 10.2 +/- 2.5 yr at the time of study. Renin release was stimulated significantly by the beta-adrenergic agonist isoproterenol in concentrations of 10(-5) M (1.67-fold) and 10(-4) M (1.84-fold). Isoproterenol-induced renin release was inhibited by atriopeptin III (ANP, 2 X 10(-8) M) and the adenylate cyclase inhibitor dideoxadenosine (DDA, 10(-5) M). Similarly, the incubation of the superficial cortical slices with arachidonic acid (10(-3) M) resulted in a 4-fold increase in tissue renin release which was blocked by the calcium ionophore A23187 (17 X 10(-6) M) and ANP; interestingly, DDA did not block arachidonic acid-induced renin release. These results suggest that ANP exerts a direct inhibitory effect on B-adrenergic and arachidonic acid-induced renin release in the primate kidney. Further, the inhibitory action of A23187 on renin release suggests, as in other species, an integral role for intracellular calcium in the renin release process. These patterns of renin release in primate kidney are similar to those observed in the rodent kidney in vitro.
...
PMID:Direct inhibitory effect of atriopeptin III on renin release in primate kidney. 295 83

The sequence of intracellular events that lead to renin release is incompletely defined. Accordingly, we examined the interrelationship of two important factors in the process: renin release coupled to cAMP and renin release related to a decrease in intracellular calcium activity (Cai). Rat renal cortical slices were used to study these relationships in vitro. In the initial studies, cAMP-coupled renin release was established for isoproterenol (10(-5) M), prostacyclin (PGI2; 10(-6) M), and forskolin (10(-5) M). Each agent caused an increase in renin release and tissue cAMP levels, which were inhibited by the addition of the adenyl cyclase inhibitor 2',5'-dideoxyadenosine (DDA, 10(-5) M) to the media. Diltiazem (10(-4) M) and 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8; 0.6 X 10(-4) M) are believed to decrease Cai by different mechanisms; each of these agents caused a significant increase in renin release. Renin release stimulated by diltiazem, and TMB-8 was not inhibited by either DDA or indomethacin. The calcium ionophore A23187 (17 X 10(-6) M) and vanadate (10(-3) M) were next added to produce an increase in Cai. Both of these agents blunted renin release produced by isoproterenol, PGI2, and forskolin. These results provide strong indirect support for an inverse relationship between Cai and renin release in the juxtaglomerular cell. The results also imply that changes in Cai occupy a step that is distal to cAMP-coupled events in the sequence of intracellular events which culminate in renin release.
...
PMID:Importance of calcium in renal renin release. 301 94

Progesterone inhibits oocyte plasma membrane adenylate cyclase measured in the presence of GTP or Gpp(NH)p by a novel mechanism that involves a guanine nucleotide regulatory protein. A hormone receptor has been identified in the oocyte plasma membranes using the technique of photoaffinity labeling, and the amount of steroid covalently bound to the steroid receptor after photolysis correlates with the level of inhibition of adenylate cyclase activity and the EC50 for germinal vesicle breakdown. Inhibition of oocyte adenylate cyclase by both progesterone and 2', 5'-dideoxyadenosine, a potent P-site agonist, correlates with slowing of guanine nucleotide exchange. The steroid inhibition shares certain other common characteristics with P-site action, including inhibition of Gpp(NH)p-stimulated enzyme activity and a slowing of the rate of Gpp(NH)p activation of the enzyme that is inversely proportional to the concentration of guanine nucleotide. The steady-state velocity of the activated enzyme is also reduced by both hormones. However, a major difference between the actions of progesterone and the P-site agonist is in the effects of the divalent cation Mn2+. Whereas Mn2+ potentiates the inhibitory action of 2', 5'-DDA, the divalent cation abolishes the inhibitory action of progesterone, as would be predicted for receptor-mediated action. The lack of effect of IAP on progesterone inhibition of oocyte adenylate cyclase suggests that progesterone inhibition of oocyte adenylate cyclase is not mediated by the IAP substrate. Possible alternative models for the IAP-insensitive steroid inhibition of oocyte adenylate cyclase include a unique interaction with Ni that is not abolished by IAP or an action that involves Ns.
...
PMID:Inhibition of Xenopus oocyte adenylate cyclase by progesterone: a novel mechanism of action. 315 86

Stereo-specific perturbation of the IgE-receptor (shown in previous studies) produces a monophasic rise in cyclic AMP that peaks at 15 s and a depletion of cyclic AMP-dependent protein kinase that plateaus at 30-60 s. The previously observed linear relationship between the attenuation in the monophasic rise in cyclic AMP and the quantity of mediator release in the presence of incremental concentrations of the adenosine analogue 2',5',-dideoxyadenosine, DDA, which is known to inhibit adenylate cyclase, indicated a direct relationship between receptor perturbation, transmembrane activation of adenylate cyclase, and granule secretion. The role of cyclic AMP as a second messenger in this sequence is now apparent from the linear relationship between net percent mediator release and net percent activation of cyclic AMP-dependent protein kinase isoenzyme when IgE-dependent activation of adenylate cyclase is suppressed by incremental quantities of DDA. There was a comparable percent activation of both types I and II mast cell cyclic AMP-dependent protein kinase isoenzymes with anti-IgE-induced activation and secretion, and there was a parallel suppression of the activation of both isoenzymes in the presence of DDA. Although these studies firmly link the activation of cytoplasmic cyclic AMP-dependent protein kinase to the IgE receptor-initiated transmembrane activation of adenylate cyclase. they do not discriminate among the functions of the two isoenzymes.
...
PMID:Mast cell mediator release as a function of cyclic AMP-dependent protein kinase activation. 627 Feb 26

A recent study from this laboratory has shown that the inflammatory mediator, interleukin-1 alpha (IL-1 alpha), stimulates protein kinase A (PKA) activity and adrenocorticotropic hormone (ACTH) secretion from AtT-20 cells without any detectable increase in intracellular cAMP accumulation. The present studies were conducted to determine if cAMP is involved in IL-1 alpha activation of PKA and if PKA is responsible for IL-1 alpha-induced ACTH release from AtT-20 cells. The data are consistent with a novel mechanism of PKA activation that does not involve cAMP. Inhibition of adenylate cyclase with 2'5'-dideoxyadenosine (2'5'-DDA) did not affect IL-1 alpha-induced increases in PKA activity and ACTH secretion. In contrast, CRF-stimulated PKA activity and ACTH secretion were inhibited by 2'5'-DDA. Additional evidence was obtained using the phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (IBMX). IBMX did not alter IL-1 alpha-induced PKA activity or ACTH secretion, yet IBMX potentiated CRF-induced cAMP accumulation. Inhibition of PKA with the PKA inhibitor, H-8, blocked activation of PKA and ACTH secretion by both IL-1 alpha and CRF in AtT-20 cells. These observations demonstrate that 1) the mechanism of IL-1 alpha activation of PKA is independent of adenylate cyclase or cAMP and 2) PKA is used by IL-1 alpha to induce ACTH secretion from AtT-20 cells.
...
PMID:Interleukin-1 increases protein kinase A activity by a cAMP-independent mechanism in AtT-20 cells. 750 95

1. The vasorelaxant activity of isoliquiritigenin, isolated from Dalbergia odorifera T, was investigated in the phenylephrine-precontracted rat aorta by measuring tension, guanylate and adenylate cyclase activities, guanosine 3':5'-cyclic monophosphate (cyclic GMP) and adenosine 3':5'-cyclic monophosphate (cyclic AMP) levels. 2. Isoliquiritigenin concentration-dependently relaxed rat aorta contracted with phenylephrine, KCl, U-46619, endothelin and 5-hydroxytryptamine, with EC50s of 7.4 +/- 1.6, 10.5 +/- 2.3, 14.3 +/- 3.3, 11.8 +/- 2.0 and 13.6 +/- 3.7 microM, respectively. 3. Isoliquiritigenin caused endothelium-independent relaxation of phenylephrine-precontracted rat aortic rings. Neither NG-monomethyl-L-arginine (L-NMMA) (an inhibitor of the L-arginine-NO pathway) nor oxyhaemoglobin (which binds NO) modified the relaxant effect of isoliquiritigenin. The relaxant action of isoliquiritigenin also persisted in intact aorta in the presence of indomethacin or glibenclamide. However, methylene blue, an inhibitor of soluble guanylate cyclase, abolished relaxation induced by isoliquiritigenin. 4. Incubation of rat aorta with isoliquiritigenin not only increased aortic cyclic GMP content but also caused small increases in aortic cyclic AMP content, and greatly potentiated the increases in cyclic AMP observed in the presence of forskolin. The maximum increase in cyclic GMP by isoliquiritigenin was reached earlier than the increase in cyclic AMP. This result suggests that the increases in cyclic GMP caused by isoliquiritigenin might stimulate the accumulation of cyclic AMP. 5. Concentration-dependent increases in soluble guanylate cyclase activity were observed in isoliquiritigenin (1-100 microM)- or sodium nitroprusside (SNP)-treated rat aortic smooth muscle cells, while adenylate cyclase activity was unchanged in isoliquiritigenin (100 microM)-treated cells. 6. Relaxation and cyclic AMP formation of rat aorta caused by isoliquiritigenin was potentiated in the presence of forskolin (10 nM), which had little effect when given alone. 2',5'-Dideoxyadenosine (DDA,200 microM), an adenylate cyclase inhibitor, diminished the relaxation and cyclic AMP formation of rat aorta by isoliquiritigenin only in the presence of forskolin. DDA did not affect the increases in cyclic GMP formation induced by isoliquiritigenin. These results suggest that elevated levels of cyclic GMP may mediate the majority of the relaxation of the phenylephrine-precontracted aorta induced byisoliquiritigenin, while the synergistic interaction with a low concentration of forskolin depends on an enhanced accumulation of cyclic AMP.7. Relaxation of phenylephrine-precontracted rat aorta and carbachol-precontracted guinea-pig trachea by rolipram (phosphodiesterase, PDE IV inhibitor) was markedly enhanced by isoliquiritigenin, while response to cilostamide (PDE III inhibitor) was not significantly changed by isoliquiritigenin.8. It is concluded that isoliquiritigenin exerts a vasorelaxant effect by activating soluble guanylatecyclase and increasing cyclic GMP. Synergistic effects of isoliquiritigenin and forskolin on muscle relaxation and cyclic AMP accumulation indicate that inhibition of cyclic AMP breakdown by cyclic GMP via the inhibition of PDE III (cyclic GMP-inhibited PDE) is the dominant mechanism.
...
PMID:Vasorelaxant effect of isoliquiritigenin, a novel soluble guanylate cyclase activator, in rat aorta. 759 26

The effects of parathyroid hormone (PTH) on sodium homeostasis in the distal tubule are not well defined. Using A6 cells as a model for distal tubular epithelium we measured equivalent short circuit current (leq), as an estimate of net sodium transport. We found that PTH increased leq in a dose-dependent manner. DDA, an agent which inhibits adenylate cyclase, decreased PTH-activated sodium transport, suggesting a role for cAMP elevation in PTH effects. Moreover, addition of Rp-cAMP, an inhibitor of cAMP-dependent protein kinase, partially blocked the PTH-stimulated leq. PTH also elicited a sustained increase in [Ca2+]i in A6 cells. This elevation in [Ca2+]i was abolished by removal of calcium from the extracellular medium, suggesting the involvement of calcium influx pathways. In fact, addition of the calcium channel blocker nitrendipine to PTH-stimulated leq partially blocked PTH-activated sodium transport. Taken together these data demonstrate that PTH stimulates electrogenic sodium transport in A6 cells and that this effect may be mediated through a rise in both intracellular calcium and cellular cAMP.
...
PMID:Parathyroid hormone stimulates electrogenic sodium transport in A6 cells. 764 25

According to our previous studies together with others, GnRH, a hypothalamic decapeptide, has been known to be a major regulator for LH release and its subunit biosynthesis in anterior pituitary gonadotropes. But the precise mechanisms by which GnRH exerts stimulatory effects on LH release and its subunit biosynthesis have not been clearly understood. In the present study we examined the effect of GnRH on protein kinase C (PKC) activity and intracellular cAMP content in cultured anterior pituitary cells of rat to clarify whether PKC or cAMP are involved in GnRH action. Moreover, we examined the effects of staurosporine (ST), a PKC inhibitor and 2',3'-dideoxyadenosine (2',3'-DDA), an adenylate cyclase inhibitor, on LH release and steady state LH beta subunit mRNA levels in cultured anterior pituitary cells of rat. PKC activity was rapidly increased within 30 min after GnRH treatment whereas intracellular cAMP level was elevated 18 h after GnRH treatment. ST significantly inhibited GnRH-induced LH release and LH beta subunit mRNA levels in a dose-dependent manner, showing an half maximal response at 50 nM ST. 2',3'-DDA inhibited GnRH-induced LH release and LH beta subunit mRNA levels in a dose-dependent manner in pituitary cells. From these results, it is suggested that GnRH stimulates LH beta subunit mRNA level as well as LH release in anterior pituitary cells and this GnRH action might be mediated by PKC activation and cAMP stimulation.
...
PMID:Effect of adenylate cyclase inhibitor and protein kinase C inhibitor on GnRH-induced LH release and LH beta subunit biosynthesis in rat anterior pituitary cells. 787 54

The effects of somatostatin (ST) on the regulation of the glomerular filtration rate have not been extensively studied. The present experiments were designed to analyze this possible relationship. ST alone did not modify the planar cell surface area (PCSA) of cultured rat mesangial cells (CRMC), but it prevented and reversed the reduction in PCSA induced by 10 nM angiotensin II (Ang II) in a dose- and time-dependent manner. ST (1 microM) completely prevented and reversed the increase in the myosin light chain phosphorylation induced by 10 nM Ang II. Incubation with pertussis toxin (PT, 0.5 micrograms/ml) inhibited the effect of ST on the Ang II-dependent changes in PCSA, but this effect was not inhibited by the blockade of the vasodilatory prostaglandins (indomethacin, 10 microM) or nitric oxide (L-N-methyl-arginine, 0.2 mM) synthesis. 2',5'-dideoxyadenosine (DDA, 0.1 mM), an adenylate cyclase blocker, and methylene blue (MB, 30 microM), a soluble guanylate cyclase blocker, did not interfere with the ST inhibitory effect on the Ang II-dependent reduction in PCSA of rat mesangial cells. ST also blocked the reduction in PCSA induced by phorbol myristate acetate (PMA, 300 nM). ST was also able to prevent and revert the Ang II dependent reduction in glomerular cross-sectional area of isolated rat glomeruli, also in a dose- and time-dependent fashion. Finally, intravenous administration of ST (200 ng/kg body wt as a bolus plus a continuous injection of 25 ng/min/kg body wt) partially blocked the reduction in GFR (measured as CIn) and RPF (measured as CPAH) and the increase in filtration fraction induced by the intravenous administration of Ang II (1.7 micrograms/min/kg body wt) in anesthetized rats. In summary, these results suggest that ST could antagonize the renal actions of Ang II, increasing the GFR and RPF decreased by Ang II, and this effect could be dependent, at least partially, on a direct relaxing effect of ST on mesangial cells.
...
PMID:Somatostatin antagonizes angiotensin II effects on mesangial cell contraction and glomerular filtration. 809 76


1 2 Next >>

---