scholarly journals Forskolin as an activator of cyclic AMP accumulation and secretion in blowfly salivary glands

1982 ◽  
Vol 204 (1) ◽  
pp. 147-151 ◽  
Author(s):  
I Litosch ◽  
Y Saito ◽  
J N Fain
Keyword(s):  
Salivary Gland ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Salivary Glands ◽  
Mammalian Cells ◽  
Salivary Secretion ◽  
Gland Secretion ◽  
Cyclic Amp Accumulation ◽  
Salivary Gland Secretion ◽  
Stimulation Of

Forskolin is a diterpene that activates adenylate cyclase in a variety of mammalian cells. In addition of forskolin to blowfly salivary glands increased cyclic AMP accumulation and salivary secretion. There was a small increase in transepithelial movement of labelled Ca2+. Forskolin did not induce breakdown of labelled phosphatidylinositol or inhibit the stimulation of phosphatidylinositol breakdown caused by 5-hydroxytryptamine. These data indicate that forskolin can mimic all the effects of 5-hydroxytryptamine on salivary-gland secretion that have been attributed to cyclic AMP.

5-HT-stimulated arachidonic acid release from labeled phosphatidylinositol in blowfly salivary glands

1982 ◽  
Vol 243 (5) ◽  
pp. C222-C226 ◽  
Author(s):  
I. Litosch ◽  
Y. Saito ◽  
J. N. Fain
Keyword(s):  
Arachidonic Acid ◽  
Salivary Gland ◽  
Salivary Glands ◽  
Gland Secretion ◽  
Appreciable Effect ◽  
Arachidonic Acid Release ◽  
Salivary Gland Secretion ◽  
Hormone Sensitive ◽  
Acid Release ◽  
Ca2 Channels

In blowfly salivary glands, breakdown of phosphatidylinositol has been linked to the activation of hormone-sensitive Ca2+ channels. Addition of 5-hydroxytryptamine to blowfly salivary glands stimulated the breakdown of phosphatidylinositol prelabeled with 32P or [3H]arachidonic acid. This was associated with a transient accumulation of [3H]arachidonic-labeled diglyceride. There was no appreciable effect of 5-hydroxytryptamine on breakdown of phosphatidylethanolamine or phosphatidylcholine labeled with 32P or [3H]arachidonic acid, indicating that phosphatidylinositol was the immediate source of diglyceride. Extracellular Ca2+ was necessary for [3H]arachidonic acid but not 32P loss from phosphatidylinositol. Addition of arachidonic acid to salivary glands did not stimulate salivary gland secretion or 45Ca flux. In contrast, 5-hydroxytryptamine stimulated both salivary gland secretion and 45Ca flux. These results indicate that, although [3H]arachidonic acid is incorporated into phosphatidylinositol and its release from this phospholipid is increased by 5-hydroxytryptamine, the liberated arachidonic acid does not stimulate salivary gland secretion or 45Ca flux.

scholarly journals Multiple non-specific effects of sphingosine on adenylate cyclase and cyclic AMP accumulation in S49 lymphoma cells preclude its use as a specific inhibitor of protein kinase C

1990 ◽  
Vol 268 (2) ◽  
pp. 507-511 ◽  
Author(s):  
J A Johnson ◽  
R B Clark
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Mammalian Cells ◽  
Specific Inhibitor ◽  
Lymphoma Cells ◽  
Specific Effects ◽  
Kinase C ◽  
Cyclic Amp Accumulation

Recent studies with phorbol esters have suggested that protein kinase C (PKC) may play a role in the regulation of adenylate cyclase in mammalian cells. Since D-sphingosine has been reported to specifically inhibit PKC in many cell types, we evaluated its effects on stimulation of cyclic AMP accumulation by adrenaline in S49 lymphoma cells. We found sphingosine to have multiple non-specific effects which could not be explained by an inhibition of PKC. These effects included: (i) inhibition by sphingosine (50 microM) of adrenaline-stimulated cyclic AMP accumulation and sphingosine permeation of the cells which rendered them leaky to ATP; (iii) sphingosine (20 microMs) augmentation of adrenaline-stimulated cyclic AMP accumulation; (iii) inhibition by sphingosine of adrenaline-stimulated adenylate cyclase in isolated membranes by up to 95%; and (iv) sphingosine (20 microM) inhibition of cellular mechanisms for the elimination of cyclic AMP. These results demonstrate the importance of evaluating the non-specific effects of sphingosine before concluding that its actions are the consequences of a specific inhibition of PKC.

Renal cyclic AMP accumulation and adenulate cyclase stimulation by erythropoietic agents

1975 ◽  
Vol 229 (5) ◽  
pp. 1387-1392 ◽  
Author(s):  
GM Rodgers ◽  
JW Fisher ◽  
WJ George
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Regional Distribution ◽  
Renal Medulla ◽  
Iron Incorporation ◽  
Erythropoietin Production ◽  
Cyclic Amp Accumulation ◽  
Stimulation Of

The regional distribution of cyclic AMP in the kidney was determined following erythropoietic stimulation with hypoxia and cobalt. Following these stimuli, increases in renal cyclic AMP concentrations were restricted to the cortex. The basis for this localization in the case of cobalt treatment was found to reside in the stimulation of renal cortical adenylate cyclase activity in vitro by concentrations of cobalt similar to those found in vivo. The level of cobalt in the cortex after cobalt treatment was found to approach 500 mumol/kg of tissue, whereas no detectable levels of cobalt were found in the renal medulla. Additionally, other agents such as parathyroid hormone and lactic acid, that are known to lack stimulatory effects on medullary adenylate cyclase, were found to stimulate the cortical enzyme. This stimulation of renal cortical adenylate cyclase correlates with enhanced erythropoiesis as demonstrated by increased radiolabeled iron incorporation into erythrocytes. These results support previous reports which suggest that renal cortical cyclic AMP mediates erythropoietin production in response to erythropoietically active agents.

scholarly journals Regulation of adenylate cyclase and cyclic AMP phosphodiesterase by 5-hydroxytryptamine and calcium ions in blowfly salivary-gland homogenates

1982 ◽  
Vol 204 (1) ◽  
pp. 153-159 ◽  
Author(s):  
I Litosch ◽  
M Fradin ◽  
M Kasaian ◽  
H S Lee ◽  
J N Fain
Keyword(s):  
Salivary Gland ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Guanine Nucleotides ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Cyclic Amp Phosphodiesterase ◽  
Maximal Stimulation ◽  
Increased Activity ◽  
Stimulation Of

Salivary-gland homogenates contain 5-hydroxytryptamine-stimulated adenylate cyclase. Half-maximal stimulation was obtained with 0.1 microM-5-hydroxytryptamine in the presence of added guanine nucleotides. Gramine antagonized the stimulation of cyclase caused by 5-hydroxytryptamine. In the presence of hormone, guanosine 5′-[gamma-thio]triphosphate produced a marked activation of adenylate cyclase activity. Stimulation of adenylate cyclase by forskolin or fluoride did not require the addition of guanine nucleotides or hormone. In the presence of EGTA, Ca2+ produced a biphasic activation of cyclase activity. Ca2+ at 1-100 microM increased activity, whereas 2000 microM-Ca2+ inhibited cyclase activity. The neuroleptic drugs trifluoperazine and chlorpromazine non-specifically inhibited adenylate cyclase activity even in the absence of Ca2+. The cyclic AMP phosphodiesterase activity in homogenates was not affected by Ca2+ or exogenous calmodulin. This enzyme was also inhibited by trifluoperazine in the absence of Ca2+. These results indicate that Ca2+ elevates adenylate cyclase activity, but had no effect on cyclic AMP phosphodiesterase of salivary-gland homogenates.

scholarly journals Proteome of Human Minor Salivary Gland Secretion

2008 ◽  
Vol 87 (5) ◽  
pp. 445-450 ◽  
Author(s):  
W.L. Siqueira ◽  
E. Salih ◽  
D.L. Wan ◽  
E.J. Helmerhorst ◽  
F.G. Oppenheim
Keyword(s):  
Mass Spectrometry ◽  
Salivary Gland ◽  
Minor Salivary Gland ◽  
Salivary Secretion ◽  
Gland Secretion ◽  
Tandem Mass ◽  
Salivary Gland Secretion ◽  
Whole Saliva ◽  
Different Characteristics ◽  
Ionization Tandem Mass Spectrometry

Recent research efforts in oral biology have resulted in elucidation of the proteomes of major human salivary secretions and whole saliva. One might hypothesize that the proteome of minor gland secretions may show significantly different characteristics when compared with the proteomes of parotid or submandibular/sublingual secretions. To test this hypothesis, we conducted the first exploration into the proteome of minor salivary gland secretion. Minor gland secretion was obtained from healthy volunteers, and its components were subjected to liquid-chromatography-electrospray-ionization-tandem-mass-spectrometry. This led to the identification of 56 proteins, 12 of which had never been identified in any salivary secretion. The unique characteristics of the minor salivary gland secretion proteome are related to the types as well as the numbers of components present. The differences between salivary proteomes may be important with respect to specific oral functions.

The foregut glands of vermivorous cone shells

1971 ◽  
Vol 19 (4) ◽  
pp. 313 ◽  
Author(s):  
H Marsh
Keyword(s):  
Salivary Gland ◽  
Salivary Glands ◽  
Protease Activity ◽  
Proteolytic Enzymes ◽  
Gland Secretion ◽  
Salivary Gland Secretion ◽  
Acid Mucosubstances

Salivary, snout, and secondary salivary glands are recorded in the foregut region of Conus Javidus, C. lividus, C. litteratus, C. miles, C. vexillum, and C. virgo. C. imperialis has a salivary gland only. The histology and histochemistry of these glands in C. Javidus and C, lividus is investigated. The salivary gland secretion consists of granules composed of polysaccharide and protein. The snout gland secretes sulphated acid mucosubstances. The secondary salivary gland secretion contains polysaccharide and protein. Protease activity was detected histochemically in the salivary gland, indicating that a function of this gland in Conus is the secretion of proteolytic enzymes into the short arm of the radular sac. The functions of the snout gland, which is peculiar to some species of Conus, and of the secondary salivary gland, which occurs sporadically throughout the Stenoglossidae, are not immediately apparent.

scholarly journals Theoretical analysis of the consequences of cyclic nucleotide phosphodiesterase negative co-operativity. Amplification and positive co-operativity of cyclic AMP accumulation

1980 ◽  
Vol 192 (1) ◽  
pp. 241-246 ◽  
Author(s):  
C Erneux ◽  
J M Boeynaems ◽  
J E Dumont
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Cyclic Nucleotide ◽  
Slight Variation ◽  
Maximal Velocity ◽  
Cyclic Nucleotide Phosphodiesterases ◽  
Accumulation Curve ◽  
Cyclic Amp Accumulation ◽  
Stimulation Of ◽  
Nucleotide Phosphodiesterases

Most tissues contain multiple forms of cyclic nucleotide phosphodiesterases (3′:5′-cyclic-nucleotide 5′ nucleotidohydrolase, EC 3.1.4.17). Consequently, in most, if not in all, tissues, substrate-velocity curves deviate from Michaelian kinetics and exhibit an apparent negative co-operativity. We have studied the possible theoretical consequences of this property on the quantitative features of cyclic AMP accumulation in response to activation of adenylate cyclase. Negative co-operativity of phosphodiesterases tends to generate a “positively co-operative” cyclic AMP accumulation curve. It amplifies the stimulation of cyclic AMP accumulation as compared with the stimulation of cyclic AMP synthesis. It enhances the sensitivity of cyclic AMP accumulation to slight variation of phosphodiesterase maximal velocity. It tends to shift the cyclic AMP accumulation curve to higher concentrations of stimulator as compared with the adenylate cyclase activation curve. This accounts for much of the data in the literature of hormonal effects on phosphodiesterase activity. It shows that the characteristics of cyclic nucleotide phosphodiesterases are as important as those of adenylate cyclase in determining the response of the system.

scholarly journals Regulation of GH3 pituitary tumour-cell adenylate cyclase activity by activators of protein kinase C

1989 ◽  
Vol 262 (3) ◽  
pp. 829-834 ◽  
Author(s):  
L A Quilliam ◽  
P R M Dobson ◽  
B L Brown
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Maximal Response ◽  
Kinase C ◽  
Cyclic Amp Accumulation ◽  
Stimulation Of

The influence of protein kinase C (PKC) activation on cyclic AMP production in GH3 cells has been studied. The stimulation of cyclic AMP accumulation induced by forskolin and cholera toxin was potentiated by 4 beta-phorbol 12,13-dibutyrate (PDBu). Moreover, PDBu, which causes attenuation of the maximal response to vasoactive intestinal polypeptide (VIP), also induced a small right shift in the dose-response curve for VIP-induced cyclic AMP accumulation. PDBu-stimulated cyclic AMP accumulation was unaffected by pretreatment of cells with pertussis toxin or the inhibitory muscarinic agonist, oxotremorine. PDBu stimulation of adenylate cyclase activity required the presence of a cytosolic factor which appeared to translocate to the plasma membrane in response to the phorbol ester. The diacylglycerol-generating agents thyroliberin, bombesin and bacterial phospholipase C each stimulated cyclic AMP accumulation, but, unlike PDBu, did not attenuate the stimulation induced by VIP. These results suggest that PKC affects at least two components of the adenylate cyclase complex. Stimulation of cyclic AMP accumulation is probably due to modification of the catalytic subunit, whereas attenuation of VIP-stimulated cyclic AMP accumulation appears to be due to the phosphorylation of a different site, which may be the VIP receptor.

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