Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activities of cyclic nucleotide phosphodiesterase were studied in rat uterus as a function of age, DNA and protein content. Linear kinetics were observed for uterine homogenate cyclic GMP (cGMP) phosphodiesterase activity, but anomalous double-reciprocal plots, suggestive of multiple enzyme forms, were observed for cyclic AMP (cAMP) hydrolysis, cAMP phosphodiesterase was therefore measured at high and low substrate concentrations, 200 muM and 0.25 muM cAMP, respectively, to approximate multiple enzyme activities. Based upon total organ content, the total cAMP and cGMP phosphodiesterase activities increased throughout uterine development, from 5-50 days of age. On the same basis, the apparent low KM cAMP phosphodiesterase increased only between days 5 and 15 and showed no significant increase between days 15 and 50. On the other hand, specific activities of an apparent low KM cAMP phosphodiesterase, expressed per mg of protein or per mug of DNA, showed a marked reduction in activity between 30 and 50 days of age. Chronic administration of 17beta-estradiol to immature rats increased their uterine protein content and decreased the specific activity of the apparent low KM cAMP phosphodiesterase. In another estrogen target tissue, the anterior pituitary, protein and DNA content also increased during development but no changes in specific activities of cyclic nucleotide phosphodiesterase were noted. These results suggest the possible participation of cyclic nucleotide phosphodiesterases in the induction of uterine growth and development by ovarian hormones.
Mol Cell Endocrinol 1975 Oct
PMID:Cyclic nucleotide phosphodiesterases in uterine development. 17 92

Bio-Gel A-5m chromatography has been used to separate apparent multiple forms of cyclic nucleotide phosphodiesterase from rat erythrocytes. Cyclic AMP phosphodiesterase was resolved by gel filtration into three peaks of activity with apparent molecular weights of about 300,000, 225,000 and 100,000, while cyclic GMP phosphodiesterase activity in gel column fractions was too low to permit meaningful estimates of its molecular weight. All three of the separated peaks of cyclic AMP phosphodiesterase activity displayed anomalous kinetic behaviour suggestive of negative cooperativity. The possibility that multiple phosphodiesterase activities could arise from in vitro alterations of a single enzyme was investigated. Similar changes in gel filtration profiles resulted when erythrocyte extracts were treated with trypsin or ammonium sulfate or were incubated at 37 degrees C. After these treatments, a large proportion of the enzyme activity occurred in low (ca. 100,000) molecular weight regions. The low molecular weight phosphodiesterase activities from untreated, incubated, and trypsin-treated extracts possessed similar properties. All were inhibited by methylxanthines, had pH optima of approximately 8.0, and similar kinetic properties and requirements for divalent cations. These observations raise the possibility that preparative procedures or limited proteolysis occurring during preparation and handling of extracts can contribute to the apparent multiplicity of enzyme forms seen after gel filtration of phosphodiesterase from rat erythrocytes and perhaps other cell types.
Mol Cell Endocrinol
PMID:Apparent multiple forms of cyclic AMP phosphodiesterase from rat erythrocytes. 18 74

The in vitro effects of insulin on different phosphodiesterase activities present in rat epididymal fat cells from normal and hypothyroid rats have been studied. Evidence is presented that insulin increases the maximum velocity of a particulate, low Km, cyclic adenosine-3', 5'-monophosphate (cyclic AMP) phosphodiesterase in both types of cells, this effect being more clearly evident with the fat cells from hypothyroid animals; combination of insulin and thyroidectomy resulted in a 400% stimulation with 10-10 - 10-9 M insulin. A clear and significant effect was apparent at 10-11 M insulin. However, the dose-response curve was biphasic, since stimulation by insulin was suppressed for doses of hormone higher 10-8 - 10-7 M. Moreover, insulin effects were very fast, since clear stimulation was observed after only 2 min of incubation; the maximal increase was obtained after 10 min. Insulin did not significantly affect the soluble cyclic AMP phosphodiesterase activity in normal cells, thus confirming results obtained by others. However, the soluble cyclic AMP phosphodiesterase activity was clearly stimulated by insulin when the fat cells were prepared from hypothyroid rats. Maximal stimulation was obtained with 10-9 M insulin; the response was again very fast. Soluble cyclic GMP phosphodiesterase activity was also increased additively by hypothyroidism and insulin, maximal stimulation being obtained with 10-9 M insulin. With this dose of insulin the additive effects of thyroidectomy and insulin produced a 5-fold stimulation. The effect of insulin on the soluble cyclic GMP phosphodiesterase was very fast (2-5 min). With both soluble cyclic nucleotide phosphodiesterase activities, insulin increased the maximal velocity but not apparent Km of the enzyme. Thus, hypothyroidism and insulin produced additive effects suggesting a different mechanism of action of these two hormonal situations on the degradation of the intracellular pools of cyclic AMP and cyclic GMP.
Mol Cell Endocrinol
PMID:Cyclic nucleotide phosphodiesterases, insulin and thyroid hormones. 18 75

Cultures of granulosa cells from immature hypophysectomized DES-treated rats were unable to maintain progestin production of more than 48 h in medium without hormone supplementation or in the presence of FSH only. Production of progestin (20alpha-dihydroprogesterone, as measured by radioimmunoassay) remained unimpaired in the presence of androstenedione (Ad) and was markedly increased in the presence of both Ad and FSH. The combined treatment with FSH and Ad during the first 48 h of culture brought about persistent changes in the cultured cells, since progestin accumulation did not decline upon subsequent removal of these hormones during days 3 and 4 of culture. Dibutyryl cyclic AMP (DBC) was able to mimic the changes in steroidogenic capability induced by the combined action of FSH and Ad. The extent of [125I]-FSH binding, FSH-stimulable cAMP accumulation and cyclic 3',5'-nucleotide phosphodiesterase activity were not affected by addition of Ad to the culture medium. Ad synergized with DBC in the stimulation of progestin accumulation in granulosa cell cultures. It is suggested that androgen acts at a step in the regulation of progestin biosynthesis distal to cAMP production.
Mol Cell Endocrinol 1977 Sep
PMID:Studies on the synergistic effect of androgen on the stimulation of progestin secretion by FSH in cultured rat granulosa cells: a search for the mechanism of action. 20 May 8

A membrane fraction prepared from isolated rat adipocytes contained an insulin-sensitive cyclic nucleotide phosphodiesterase (EC 3.1.4.17) which catalyzed the hydrolysis of both adenosine 3',5'-monophosphate (cAMP) and guanosine 3',5'-monophosphate (cGMP). The rate of hydrolysis of cGMP was about one-third that of cAMP. The hydrolysis of the two nucleotides appeared to be assoicated with one catalytic site: one nucleotide interfered with the hydrolysis of the other, in a manner predictable from the kinetic constants in that the Km of one nucleotide as a substrate was comparable to its Ki as an inhibitor of the hydrolysis of the other nucleotide. Incubation of the adipocytes with insulin increased the Vmax of phosphodiesterase without affecting the Km values for either substrate. After adipocytes had been treated with filipin, a membrane perturbant, at a concentration that did not cause cell lysis, the response of phosphodiesterase to insulin was obliterated. Further, the insulin-stimulated phosphodiesterase activity was reversed when hormone-treated cells were subsequently incubated with this agent. These results suggest that the response of membrane phosphodiesterase to insulin is impaired once adipocytes have been exposed to filipin, either preceding or following the incubation with insulin.
Mol Cell Endocrinol 1979 May
PMID:Filipin prevents and reverses insulin stimulation of rat adipocyte phosphodiesterase. 22 98

Analysis of cyclic nucleotide phosphodiesterase (PDE) activity in cellular fractions from cultured rat pheochromocytoma (PC12) cells has shown that the predominant hydrolytic activity in both cytosolic and particulate compartments is characteristic of a PDE II, the cGMP-activatable family of PDE isozymes. Cytosolic PDE activity was purified to a high degree utilizing DE-52 anion exchange and cGMP-Sepharose affinity chromatographies. The physicochemical properties of PC12 PDE II were similar to those of PDE II isolated from particulate or soluble fractions of other tissues, including subunit molecular weight of approximately 102,000, activation of cAMP hydrolysis by cGMP, and positive cooperative kinetic behavior for cAMP and cGMP hydrolysis. The potential role of PDE II in regulating cAMP metabolism in intact PC12 cells was studied using an [3H]adenine prelabeling technique. Stimulation of PC12 cell adenosine receptors resulted in a 5-8-fold increase in cAMP accumulation. Removal of the adenosine stimulus by the addition of exogenous adenosine deaminase resulted in a rapid decay of cAMP to prestimulated basal levels within 2 min. Treatment of PC12 cells with atrial natriuretic factor or sodium nitroprusside caused 1) increased intracellular cGMP levels, 2) attenuation of adenosine-stimulated cAMP accumulation, and 3) increased rates of cAMP decay after removal of the adenosine stimulus. Treatment of PC12 cells with HL-725 (a potent inhibitor of isolated PDE II activity in vitro) caused 1) increased basal cAMP accumulation, 2) potentiation of adenosine-stimulated cAMP accumulation, and 3) retardation of the rate of cAMP decay after removal of the adenosine stimulus. HL-725 blocked both the attenuation of cAMP accumulation and the accelerated rate of cAMP decay observed with the cGMP-elevating agents. These results suggest that, in PC12 cells, drugs or hormones that inhibit PDE II or increase intracellular cGMP levels to activate PDE II can modulate cAMP metabolism by altering the catalytic status of the enzyme.
Mol Pharmacol 1991 Jun
PMID:Phosphodiesterase II, the cGMP-activatable cyclic nucleotide phosphodiesterase, regulates cyclic AMP metabolism in PC12 cells. 164 46

The role of individual cyclic nucleotide phosphodiesterase (PDE) isozymes in regulating cAMP and cGMP content in intact canine trachealis was examined using isozyme-selective and nonselective PDE inhibitors. The inhibitors used in this study were characterized previously [Mol. Pharmacol. 37:206-214 (1990)] and included: 1) zaprinast, an inhibitor (Ki = 0.1 microM) of the cGMP-specific PDE (cAMP Km = 135 microM; cGMP Km = 4 microM); 2) SK&F 94120, an inhibitor (Ki = 7 microM) of the cGMP-inhibited PDE (cAMP Km = 0.3 microM; cGMP Km = 8 microM); 3) Ro 20-1724, an inhibitor (Ki = 5 microM) of the cAMP-specific PDE (cAMP Km = 4 microM; cGMP Km = 40 microM); and 4) 3-isobutyl-1-methylxanthine (IBMX), a nonselective PDE inhibitor (IC50 = 1-30 microM). In addition to the aforementioned isozymes, canine trachealis contains a Ca2+/calmodulin-stimulated PDE (cAMP Km = 1 microM; cGMP Km = 2 microM) and a GMP-stimulated PDE (cAMP Km = 93 microM; cGMP Km = 60 microM), for which selective inhibitors are not available. Isolated canine trachealis strips were contracted with methacholine and exposed to various concentrations of PDE inhibitors, before being relaxed by the cumulative addition of isoproterenol, an adenylate cyclase activator, or sodium nitroprusside, a guanylate cyclase activator. At the completion of the concentration-response studies, tissues were flash-frozen and assayed for cyclic nucleotide content. Neither isoproterenol-induced relaxation nor cAMP accumulation was altered by zaprinast, but both of these responses were potentiated by pretreatment of tissues with either SK&F 94120 or Ro 20-1724. The effects of SK&F 94120 and Ro 20-1724 were additive, and the combination of SK&F 94120, Ro-1724, and IBMX had no greater effect on the responses to isoproperenol than did either IBMX alone or the combination of SK&F 94120 plus Ro 20-1724. In contrast, zaprinast potentiated sodium nitroprusside-induced relaxation and cGMP accumulation, whereas neither SK&F 94120 nor Ro 20-1724 altered these responses. IBMX produced a greater potentiation than did zaprinast, and the combination of zaprinast and IBMX had a greater effect than either agent alone. The results of this study suggest that the cGMP-inhibited and cAMP-specific PDEs are responsible for cAMP hydrolysis in intact canine trachealis, whereas cGMP hydrolysis is mediated by the cGMP-specific PDE as well as the Ca2+/calmodulin-stimulated PDE and/or the cGMP-stimulated PDE.
Mol Pharmacol 1991 Mar
PMID:Role of cyclic nucleotide phosphodiesterase isozymes in intact canine trachealis. 184 59

A novel molecule from the arylalkylamine family of drugs, KHL-8430, has been identified as a potent and specific inhibitor of calmodulin activity. The effect of this drug on calmodulin-mediated enzymatic actions has been analyzed to exemplify how to model the mechanism of action of a functional calmodulin antagonist. The approach used includes both binding and enzyme kinetic studies. In both types of experiments, the effects of drugs on calmodulin-phosphofructokinase [ATP:D[fructose-6-phosphate-1-phosphotransferase, EC 2.7.1.11] and calmodulin-phosphodiesterase (3':5' cyclic nucleotide phosphodiesterase, EC 3.6.1.3) interactions have been investigated. We have found that KHL-8430, in contrast to trifluoperazine, a classical anticalmodulin drug, competes with neither phosphofructokinase nor phosphodiesterase for calmodulin binding, yet it liberates phosphofructokinase from calmodulin inhibition and phosphodiesterase from calmodulin stimulation. The anticalmodulin activity occurs at lower KHL-8430 than trifluoperazine concentrations. These findings might establish the functional importance of these differences in the specificity of these drugs. The synthesis of the data suggests that (i) whereas trifluoperazine antagonizes both phosphofructokinase and phosphodiesterase binding to calmodulin, KHL-8430 interacts with calmodulin complexed with enzymes; (ii) KHL-8430 binds to the calmodulin-phosphofructokinase complex with an affinity constant of 0.8 microM, whereas the binding constant of trifluoperazine is 2.5 microM (iii) within the ternary complex the dimeric form of the kinase preserves activity that is otherwise inactive; and (iv) the binding of trifluoperazine and KHL-8430 to calmodulin exhibits negative cooperativity. The approach used in this study makes it possible to screen for the calmodulin antagonist effect of other drugs as well.
Mol Pharmacol 1990 Dec
PMID:Dissimilar mechanisms of action of anticalmodulin drugs: quantitative analysis. 214 57

The cyclic nucleotide phosphodiesterase (phosphodiesterase) plays essential roles throughout the development of Dictyostelium discoideum. It is crucial to cellular aggregation and to postaggregation morphogenesis. The phosphodiesterase gene is transcribed into three mRNAs, containing the same coding sequence connected to different 5' untranslated sequences, that accumulate at different times during the life cycle. A 1.9-kilobase (kb) mRNA is specific for growth, a 2.4-kb mRNA is specific for aggregation, and a 2.2-kb mRNA is specific for late development and is only expressed in prestalk cells. Hybridization of RNA isolated from cells at various stages of development with different upstream regions of the gene indicated separate promoters for each of the three mRNAs. The existence of specific promoters was confirmed by fusing the three putative promoter regions to the chloramphenicol acetyltransferase reporter gene, and the analysis of transformants containing these constructs. The three promoters are scattered within a 4.1-kilobase pair (kbp) region upstream of the initiation codon. The late promoter is proximal to the coding sequence, the growth-specific promoter has an initiation site that is 1.9 kbp upstream of the ATG codon, and the aggregation-specific promoter has an initiation site 3 kbp upstream.
Mol Cell Biol 1990 May
PMID:The cyclic nucleotide phosphodiesterase gene of Dictyostelium discoideum contains three promoters specific for growth, aggregation, and late development. 215 67

Tissue levels of 3'-AMP were measured in several rat tissues and the sensitivities of the respective adenylyl cyclases were compared with respect to "P" site-mediated inhibition by 3'-AMP2'-deoxy-3'AMP (2'd3'-AMP), and 2',5'-dideoxyadenosine. IC50 values for these P site inhibitors of adenylyl cyclases varied widely among tissues, e.g., with skeletal muscle being least sensitive to 3'-AMP (IC50 greater than 170 microM) and brain being most sensitive (IC50 approximately 10 microM). These differences were noted when activation was with Mn2+ but diminished with Mn2+ plus forskolin and conceivably may reflect the distribution of different isozymes of adenylyl cyclase. 3'-AMP levels also varied significantly among rat tissues, with spleen having the highest levels (approximately 280 nmol/g), kidney, liver, heart, and brain having decreasing 3'-AMP content, and skeletal muscle levels being immeasureably low (less than 0.1 nmol/g). When rats were made diabetic with streptozotocin, the 3'-AMP content of livers increased from approximately 47 nmol/g in control animals to approximately 84 nmol/g, a change largely reversed by maintenance of diabetic animals with insulin. The data suggest that tissue 3'-AMP levels may be regulated and in certain tissues may be sufficient to inhibit adenylyl cyclase in vivo. Three potential sources of 3'-AMP and 2'd3'-AMP, the most potent naturally occurring P site inhibitors of adenylyl cyclase, were examined. No evidence was found for the formation of either nucleotide from the respective cyclic nucleotide by a unique cyclic nucleotide phosphodiesterase or from the respective nucleoside by a hypothetical adenosine 3'-kinase and ATP. Substantial 3'-AMP and 2'd3-AMP were formed by spleen and liver homogenates from the respective oligonucleotides (RNA, mRNA, and DNA) in a time- and protein-dependent manner. The data imply the existence of enzymes in these tissues to catalyze the formation of 3'-AMP and 2'd3'-AMP from nucleic acids and suggest that these activities may account for the formation of P site agonists under in vivo conditions. The data suggest that these P site inhibitors are a potential link between fluctuations in nucleic acid metabolism and altered sensitivity of membrane-bound adenylyl cyclase to stimulatory signals.
Mol Pharmacol 1990 Dec
PMID:Tissue levels, source, and regulation of 3'-AMP: an intracellular inhibitor of adenylyl cyclases. 217 5


1 2 3 4 5 6 7 8 9 10 Next >>