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:3.4.15.1 (ACE)
18,300 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Captopril (CA), a specific inhibitor of kininase II, did not alter osmotic water permeability (Posm) when present in the mucosal bath of the urinary bladder isolated from the toad Bufo arenarum at a concentration of 2.3 X 10(-3) M. This treatment, however, caused a 65% enhancement in the increase in Posm following serosal exposure to vasopressin, oxytocin or theophylline, agents that increase intracellular cyclic AMP levels. The effect of captopril was prevented by procedures that reduce the kallikrein (KK)-like alkaline esterase activity present in the bladder (such as simultaneous exposure to 2.3 X 10(-5) M aprotinin, or pretreatment of the toads with 0.1 N NaCl for several days before the experiment) or by replacing the mucosal bath with fresh solution of identical composition after exposure to captopril. In contrast, changing the serosal bath did not alter the effect of the drug. These results are consistent with an effect of CA at a step beyond cAMP generation, and suggest it is mediated by release of a soluble factor, probably a kinin, into the mucosal bath. These observations, together with data previously published, suggest that the KK-kinin system may participate in the control of epithelial water and electrolyte permeability in the toad bladder. In particular, under environmental stress, it may become important in the regulation of the animal's extracellular fluid volume, thus exhibiting an adaptive value.
...
PMID:A role for the kallikrein-kinin system in the regulation of osmotic water permeability in the toad bladder. 287 44

This study investigates the endogenous kallikrein-kinin system's role as a modulator of vasopressin action in the toad urinary bladder. Kalli-krein inhibition by aprotinin, which results in decreased kinin production, significantly increased both vasopressin and 8-Br-cyclic (c) AMP-stimulated water flow. Kinin potentiation by the kininase II inhibitor captopril (SQ 14225) significantly decreased vasopressin and 8-Br-cAMP-stimulated water flow. In contrast to water flow, vasopressin-stimulated urea permeability was decreased by aprotinin and increased by captopril. We conclude that the endogenous kallikrein-kinin system represents a significant modulator of vasopressin action and it permits separate control of vasopressin-stimulated water flow and solute transport.
...
PMID:Role of the endogenous kallikrein-kinin system in modulating vasopressin-stimulated water flow and urea permeability in the toad urinary bladder. 616 39

The potential of the CREM family of proteins to activate transcription of the genes encoding the testis-specific isozyme of angiotensin converting enzyme (ACET) and the gluconeogenic enzyme, phosphoenolpyruvate carboxykinase (GTP) (PEPCK) (EC 4.1.1.32) were investigated. Both CREM tau and CREM alpha bind efficiently to the putative cyclic AMP response element (CRE) present in the ACET gene (CRET) and to the CRE in the PEPCK gene. In HepG2 cells, the CRE was required for the strong stimulation by CREM tau of the expression of a chimeric PEPCK (-210 to +73)-chloramphenicol acetyl transferase (CAT) gene. The CRE could be mutated to the CRET sequence without losing the stimulatory effects of CREM tau. However, a similar chimeric gene driven by the regulatory region of the ACET gene, which contains the CRET site, could only be stimulated by CREM tau when its imperfect TATA element was mutated to an authentic TATA. Surprisingly, CREM alpha, an alleged inhibitor of CRE-mediated transcription, stimulated the expression of both PEPCK-CAT and ACET-CAT genes in HepG2 cells, a process which required the presence of the CRE and the CRET sites, respectively. In contrast, when the same CRE elements were used to drive the transcription of a chimeric gene containing the thymidine kinase promoter linked to the CAT structural gene, CREM alpha inhibited its expression in HepG2 and JEG3 cells. The expression of the same chimeric gene, however, was stimulated by CREM alpha in F9 embryonal carcinoma cells. These results demonstrated that the nature of the transcriptional effects of CREM isoforms on CRE-mediated transcription depends on the specific gene, the specific cell type and the promoter context of the CRE site.
...
PMID:The cyclic AMP response elements of the genes for angiotensin converting enzyme and phosphoenolpyruvate carboxykinase (GTP) can mediate transcriptional activation by CREM tau and CREM alpha. 764 72

Testis angiotensin-converting enzyme (testis ACE) is an isozyme of ACE only expressed by male germ cells during spermiogenesis. It is the result of a strong sperm-specific promoter found within the 12th intron of the somatic ACE gene. Previous studies have localized the boundaries of the mouse testis ACE promoter as being from -91 to -9, relative to the transcriptional start site, and have suggested two important DNA regulatory elements starting at positions -55 and -32. DNA constructs were made in which these motifs were either eliminated or substituted. Each construct was tested for its ability to promote transcription in vitro, using a rat testis nuclear extract. Disruption of either motif reduced in vitro transcription to about 30% of control levels, while mutations of both elements abolished transcription. Two sites were selected inside each motif and altered by point mutation. Each of four constructs, containing a mutation at -51, -48, -30, or -28, transcribed at 29% or less the efficiency of the parent construct. The DNA element at -55, TGAGGTCA, is homologous to a consensus cyclic AMP response element. The motif at -32, TCTTAT, is located at a position analogous to a TATA box. Substitution of the -32 motif with a consensus TATA box sequence, TATAAA, stimulated transcriptional activity about 3-fold. As measured by gel mobility shift, oligonucleotides encompassing the -32 motif and the consensus TATA box formed different DNA-protein complexes. However, the -32 motif oligonucleotide was recognized by nuclear proteins prepared from either liver or testis nuclei.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Identification of two positive transcriptional elements within the 91-base pair promoter for mouse testis angiotensin converting enzyme (testis ACE). 773 68

The gene encoding the testis isozyme of angiotensin-converting enzyme (testis ACE) is one example of the many genes expressed uniquely during spermatogenesis. This protein is expressed by developing germ cells late in their development and results from the activation of a sperm-specific promoter that is located within intron 12 of the gene encoding the somatic isozyme of ACE. In vitro transcription, DNase footprinting, gel shift assays, and transgenic mouse studies have been used to define the minimal testes ACE promoter and to characterize DNA-protein interactions mediating germ cell-specific expression. These studies show that proper cell- and stage-specific expression of testis ACE requires only a small portion of the immediate upstream sequence extending to -91. A critical motif within this core promoter is a cyclic AMP-responsive element sequence that interacts with a testis-specific transactivating factor. Since this putative cyclic AMP-responsive element has been conserved within the testis ACE promoters of different species and is found at the same site in other genes that are expressed specifically in the testis, it may provide a common mechanism for the recognition of sperm-specific promoters.
...
PMID:Sperm-specific expression of angiotensin-converting enzyme (ACE) is mediated by a 91-base-pair promoter containing a CRE-like element. 838 Feb 20

Testis angiotensin-converting enzyme (testis ACE), an ACE isozyme that plays an important role in male fertility, is transcribed from a unique promotor active only in developing spermatids. In vitro analysis suggests the importance of a cyclic AMP response element (CRE)-like region within the testis ACE promoter, and similar DNA motifs are important in the expression of a variety of testis-specific genes. In the present study, we examined the effects of mutations in the CRE-like element on testis ACE promoter activity in vivo using transgenic mice. Disruption of this element reduced reporter gene expression to near background levels. In contrast, conversion of the CRE-like element to a consensus CRE-binding site resulted in high level expression of the reporter gene specifically in the testis. These experiments prove that the CRE-like element is essential for testis ACE promoter activity, although it does not appear to be responsible for its tissue specificity. These data provide insight into how a phenotypically differentiated tissue, ie, male gem cells, regulate tissue-specific gene expression.
...
PMID:Expression of testis angiotensin-converting enzyme is mediated by a cyclic AMP responsive element. 938 91

The study examined the existence and regulation of fat-carbohydrate interaction during low- and moderate-intensity exercise. Eight males cycled for 10 min at 40% and 60 min at 65% maximal O2 uptake (VO2max) while infused with either Intralipid and heparin (Int) or saline (Con). Before exercise, plasma arterial free fatty acid (FFA) was 0.69 +/- 0.04 mM (Int) vs. 0.25 +/- 0.04 mM (Con). Muscle biopsies were taken at rest and at 10, 20, and 70 min of exercise. Arterial and femoral venous blood samples and expired gases were collected simultaneously throughout exercise, and blood flow was estimated from pulmonary O2 uptake and the leg arterial-venous O2 difference. Respiratory exchange ratio was higher in Con (0.94 +/- 0.01) compared with Int (0.91 +/- 0.01). Mean net leg FFA uptake was higher in Int (0.16 +/- 0.03 vs. 0.04 +/- 0.01 mmol/min), and net lactate efflux was reduced (Int, 1.55 +/- 0.36 vs. Con, 3.07 +/- 0.47 mmol/min). Leg net glucose uptake was unaffected by Int. Muscle glycogen degradation was 23% lower in Int [230 +/- 29 vs. 297 +/- 36 mmol glucosyl units/kg dry muscle (dm)]. Pyruvate dehydrogenase activity in the a form (PDHa) was lower during Int (1.61 +/- 0.17 vs. 2.22 +/- 0.24 mmol.min-1.kg wet muscle-1), and muscle citrate was higher (0.59 +/- 0.04 vs. 0.48 +/- 0.04 mmol/kg dm). Muscle lactate, phosphocreatine, ATP, acetyl-CoA, acetyl-carnitine, and P(i) were unaffected by Int. Calculated free AMP was significantly lower in Int compared with Con at 70 min of exercise (3.3 +/- 0.8 vs. 1.5 +/- 0.3 mumol/kg dm). The high FFA-induced reduction in glycogenolysis and carbohydrate oxidation at 65% VO2max appears to be due to regulation at several sites. The reduced flux through phosphorylase and phosphofructokinase during Int may have been due to reduced free AMP accumulation and increased cytoplasmic citrate. The mechanism for reduced PDH transformation to the a form is unknown but suggests reduced flux through PDH.
...
PMID:Effects of increased fat availability on fat-carbohydrate interaction during prolonged exercise in men. 957 49

The purpose of the study was to examine the roles of active pyruvate dehydrogenase (PDH(a)), glycogen phosphorylase (Phos), and their regulators in lactate (Lac(-)) metabolism during incremental exercise after ingestion of 0.3 g/kg of either NaHCO(3) [metabolic alkalosis (ALK)] or CaCO(3) [control (CON)]. Subjects (n = 8) were studied at rest, rest postingestion, and during constant rate cycling at three stages (15 min each): 30, 60, 75% of maximal O(2) uptake (VO(2 max)). Radial artery and femoral venous blood samples, leg blood flow, and biopsies of the vastus lateralis were obtained during each power output. ALK resulted in significantly (P < 0.05) higher intramuscular Lac(-) concentration ([Lac(-)]; ALK 72.8 vs. CON 65.2 mmol/kg dry wt), arterial whole blood [Lac(-)] (ALK 8.7 vs. CON 7.0 mmol/l), and leg Lac(-) efflux (ALK 10.0 vs. CON 4.2 mmol/min) at 75% VO(2 max). The increased intramuscular [Lac(-)] resulted from increased pyruvate production due to stimulation of glycogenolysis at the level of Phos a and phosphofructokinase due to allosteric regulation mediated by increased free ADP (ADP(f)), free AMP (AMP(f)), and free P(i) concentrations. PDH(a) increased with ALK at 60% VO(2 max) but was similar to CON at 75% VO(2 max). The increased PDH(a) may have resulted from alterations in the acetyl-CoA, ADP(f), pyruvate, NADH, and H(+) concentrations leading to a lower relative activity of PDH kinase, whereas the similar values at 75% VO(2 max) may have reflected maximal activation. The results demonstrate that imposed metabolic alkalosis in skeletal muscle results in acceleration of glycogenolysis at the level of Phos relative to maximal PDH activation, resulting in a mismatch between the rates of pyruvate production and oxidation resulting in an increase in Lac(-) production.
...
PMID:Effect of induced metabolic alkalosis on human skeletal muscle metabolism during exercise. 1066 17

The present study examined the acute effects of hypoxia on the regulation of skeletal muscle metabolism at rest and during 15 min of submaximal exercise. Subjects exercised on two occasions for 15 min at 55% of their normoxic maximal oxygen uptake while breathing 11% O(2) (hypoxia) or room air (normoxia). Muscle biopsies were taken at rest and after 1 and 15 min of exercise. At rest, no effects on muscle metabolism were observed in response to hypoxia. In the 1st min of exercise, glycogenolysis was significantly greater in hypoxia compared with normoxia. This small difference in glycogenolysis was associated with a tendency toward a greater concentration of substrate, free P(i), in hypoxia compared with normoxia. Pyruvate dehydrogenase activity (PDH(a)) was lower in hypoxia at 1 min compared with normoxia, resulting in a reduced rate of pyruvate oxidation and a greater lactate accumulation. During the last 14 min of exercise, glycogenolysis was greater in hypoxia despite a lower mole fraction of phosphorylase a. The greater glycogenolytic rate was maintained posttransformationally through significantly higher free [AMP] and [P(i)]. At the end of exercise, PDH(a) was greater in hypoxia compared with normoxia, contributing to a greater rate of pyruvate oxidation. Because of the higher glycogenolytic rate in hypoxia, the rate of pyruvate production continued to exceed the rate of pyruvate oxidation, resulting in significant lactate accumulation in hypoxia compared with no further lactate accumulation in normoxia. Hence, the elevated lactate production associated with hypoxia at the same absolute workload could in part be explained by the effects of hypoxia on the activities of the rate-limiting enzymes, phosphorylase and PDH, which regulate the rates of pyruvate production and pyruvate oxidation, respectively.
...
PMID:Regulation of glycogen phosphorylase and PDH during exercise in human skeletal muscle during hypoxia. 1071 May 8

The study investigates relationship between simple renal cyst enlargement studied by ultrasonography and anti-hypertensive treatment. To this purpose we enrolled 42 patients with newly diagnosed hypertension affected by simple renal cysts. Fourteen were randomly assigned to treatment with ACE-Inhibitors (group 1), twelve to diuretics (group 2) and sixteen to Ca-Antagonists (group 3). Patient performed a basal ultrasonography to evaluate basal cyst dimension before starting anti-hypertensive treatment. Following 12 months of the anti-hypertensive regimen, a new echograph was performed to evaluate changes in cyst size. A control group consisting of 15 patients with normal blood pressure and simple renal cysts was enrolled (group 0). An enlargement of cysts was detected in all patients. However, the enlargement observed in patients treated by Ca-Antagonists was significantly greater than that observed in the other groups (p<0.05). Our study supports the hypothesis that Ca-Antagonists may favor cyst enlargement by enhancing cyclic AMP production. In fact, cAMP and cAMP agonists stimulate fluid secretion by lining cells of the cyst wall, inducing cyst enlargement.
...
PMID:Simple renal cysts in hypertensive patients: relation between cyst growing and anti-hypertensive therapy. 1279 9


<< Previous 1 2 3 4 Next >>

---