Inhibitory effect of thyroid hormones on pituitary cyclic AMP phosphodiesterase activity in vitro

1984 ◽  
Vol 9 (7) ◽  
pp. 1011-1018 ◽  
Author(s):  
Akio Nagasaka ◽  
Hiroyoshi Hidaka ◽  
Kunitaka Kataoka ◽  
Katsumi Iwase ◽  
Hifumi Nakagawa ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Thyroid Hormones ◽  
Inhibitory Effect ◽  
Phosphodiesterase Activity ◽  
Cyclic Amp Phosphodiesterase

scholarly journals Long-term effects of a high glucose concentration on cyclic nucleotide phosphodiesterase activity in mouse pancreatic islets maintained in tissue culture

1976 ◽  
Vol 156 (2) ◽  
pp. 461-463 ◽  
Author(s):  
C Berne ◽  
A Andersson
Keyword(s):  
Cyclic Amp ◽  
Pancreatic Islets ◽  
Glucose Concentration ◽  
Phosphodiesterase Activity ◽  
Long Term Effects ◽  
Isolated Pancreatic Islets ◽  
Cyclic Amp Phosphodiesterase ◽  
Extracellular Glucose Concentration ◽  
Extracellular Glucose

It has been suggested that the stimulatory effect of glucose on insulin release may be mediated by the adenylate cyclase-cyclic AMP phosphodiesterase system. In this study it was found that exposure of isolated pancreatic islets to an elevated extracellular glucose concentration for 1 week in vitro caused an increase of the cyclic AMP phosphodiesterase activity in the islet cells. These and previous data indicate that there is an increased turnover of cyclic AMP in B-cells exposed for a prolonged time to a high extracellular glucose concentration, which also causes an increased turnover rate of insulin.

Cyclic AMP phosphodiesterase activity in the hearts of trained rats

1983 ◽  
Vol 61 (9) ◽  
pp. 1017-1024
Author(s):  
Warren K. Palmer ◽  
Sylvia Doukas
Keyword(s):  
Enzyme Activity ◽  
Cyclic Amp ◽  
Total Concentration ◽  
Chelating Agent ◽  
Phosphodiesterase Activity ◽  
Cyclic Amp Phosphodiesterase ◽  
Rat Hearts ◽  
Elevated Activity ◽  
And Control

Running exercise trained rats at either 60 or 76% of their [Formula: see text] caused myocardial cyclic AMP phosphodiesterase (PDE) activity to be increased above control levels for at least 24 h following work. Neither training nor the exercise had any effect on the total concentration of calmodulin in heart tissues. The affinity of PDE for cyclic AMP was not changed by the exercise or training. The chelating agent, EGTA, had the same influence on PDE activity regardless of whether it was present in assays of control or exercised heart extract. Km and EGTA results suggest that calcium-bound calmodulin does not account for the higher PDE activity in the hearts of exercised rats. Supernatants from hearts homogenized in the presence of charcoal, to remove nucleotides from the extract, did not eliminate the exercise-associated increase in PDE activity. These results suggest that the elevated activity was not caused by an in vitro nucleotide activation. Preincubation of the enzyme from exercised and control rat hearts with snake venom activated PDE when assays were performed with the low concentration of cyclic AMP (1 μM). Moreover, the activity reached in the extract of exercisers (23.3 pmol∙100 μL−1∙min−1) was significantly greater than the activity found in control hearts (17.59 pmol∙100 μL−1∙min−1). Exercise increases PDE activity in the myocardium of trained rats. The results presented suggest that the increased PDE activity resulting from exercise is not dependent upon exercise intensity when the work is in excess of 60% of [Formula: see text]. In addition, the data obtained using indirect probes suggest that the increased enzyme activity was not caused by metabolites, endogenous nucleotides, or calmodulin changes in the hearts of exercised animals.

scholarly journals Calmodulin activation of cyclic AMP phosphodiesterase in the B16 mouse melanoma

1984 ◽  
Vol 219 (3) ◽  
pp. 941-946 ◽  
Author(s):  
S W Walker ◽  
S Mac Neil ◽  
H J Senior ◽  
S S Bleehen ◽  
S Tomlinson
Keyword(s):  
Cyclic Amp ◽  
Cultured Cells ◽  
Soluble Fraction ◽  
Inhibitory Effect ◽  
Tumour Tissue ◽  
Phosphodiesterase Activity ◽  
Calmodulin Antagonist ◽  
Mouse Melanoma ◽  
Cyclic Amp Phosphodiesterase ◽  
B16 Mouse Melanoma

Mouse B16 melanoma extracts of both cultured cells and tumour tissue contain cyclic AMP phosphodiesterase activity, with 95% present in the soluble fraction. Although activation of the enzyme by added calmodulin did not occur, it was found that endogenous calmodulin was present at a level sufficient to activate fully the enzyme. The ability of Ca-calmodulin to stimulate cyclic AMP phosphodiesterase in this tissue was shown by the inhibitory effect of N-(6-aminohexyl)-5-chloronaphthalenesulphonamide (W7), a known calmodulin antagonist; by the activation of the enzyme with exogenous calmodulin observed in supernatants depleted of endogenous calmodulin by passage over fluphenazine-Sepharose 6B in the presence of Ca2+; by the Ca-dependent binding of the enzyme to calmodulin-agarose and its activation by Ca-calmodulin after elution from the column with EGTA-containing buffer. It was calculated that about 50% of the total cyclic AMP phosphodiesterase activity was calmodulin-activated in this tissue.

In Vitro Effects of Ethanol on Rabbit Platelet Aggregation, Secretion of Granule Contents, and Cyclic AMP Levels in the Presence of Prostacyclin

1989 ◽  
Vol 61 (02) ◽  
pp. 254-258 ◽  
Author(s):  
Margaret L Rand ◽  
Peter L Gross ◽  
Donna M Jakowec ◽  
Marian A Packham ◽  
J Fraser Mustard
Keyword(s):  
Cyclic Amp ◽  
Inhibitory Effect ◽  
Rabbit Platelet ◽  
Inhibitory Effects ◽  
Low Concentrations ◽  
Rabbit Platelets ◽  
High Concentrations ◽  
In Vitro Effects ◽  
Aggregation Of Platelets

SummaryEthanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.

Effect of Cyclic AMP and Cyclic GMP on Thromboplastin (Factor III) Synthesis in Human Monocytes In Vitro

1983 ◽  
Vol 50 (04) ◽  
pp. 804-809 ◽  
Author(s):  
Torstein Lyberg
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Immune Complexes ◽  
Phosphodiesterase Inhibitors ◽  
Inhibitory Effect ◽  
Intracellular Camp ◽  
Human Monocytes ◽  
Purified Protein Derivative ◽  
A 23187

SummaryHuman monocytes in vitro respond to various agents (immune complexes, lectins, endotoxin, the divalent ionophore A 23187, 12-0-tetradecanoyl-phorbol 13-acetate [TPA], purified protein derivative [PPD] of Bacille Calmette-Guerin) with an increased synthesis of the protein component of thromboplastin. The effect of cyclic AMP and cyclic GMP on this response has been studied. Dibutyryl-cyclic AMP, prostaglandin E1 and the phosphodiesterase inhibitors 3-butyl-1-methyl-xanthine (MIX) and rac -4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (Ro 201724), separately and in combination have a pronounced inhibitory effect on the response to immune complexes and PPD, and a moderate effect on the response to endotoxin and lectins. The effect on TPA response and on the response to A 23187 was slight. Dibutyryl-cyclic GMP (1 mM) gave a slight inhibition of the TPA arid IC response, but had essentially no effect on the response to other inducers. The intracellular cAMP level increased when monocytes were incubated with IC, TPA or A 23187 followed by a decrease to basal levels within 1-2 hr, whereas lectin (PHA) and PPD did not induce such changes. The cAMP response to endotoxin varied. Stimulation with IC induced an increase in monocyte cGMP levels, whereas the other stimulants did not cause such changes.

Cloning and characterization of the low-affinity cyclic AMP phosphodiesterase gene of Saccharomyces cerevisiae

1987 ◽  
Vol 7 (10) ◽  
pp. 3629-3636
Author(s):  
J Nikawa ◽  
P Sass ◽  
M Wigler
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cyclic Amp ◽  
Copy Number ◽  
Growth Arrest ◽  
Yeast Cells ◽  
Phosphodiesterase Activity ◽  
Camp Phosphodiesterase ◽  
High Affinity ◽  
Cyclic Amp Phosphodiesterase

Saccharomyces cerevisiae contains two genes which encode cyclic AMP (cAMP) phosphodiesterase. We previously isolated and characterized PDE2, which encodes a high-affinity cAMP phosphodiesterase. We have now isolated the PDE1 gene of S. cerevisiae, which encodes a low-affinity cAMP phosphodiesterase. These two genes represent highly divergent branches in the evolution of phosphodiesterases. High-copy-number plasmids containing either PDE1 or PDE2 can reverse the growth arrest defects of yeast cells carrying the RAS2(Val-19) mutation. PDE1 and PDE2 appear to account for the aggregate cAMP phosphodiesterase activity of S. cerevisiae. Disruption of both PDE genes results in a phenotype which resembles that induced by the RAS2(Val-19) mutation. pde1- pde2- ras1- ras2- cells are viable.

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