Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0403608 (ureter)
 9,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepatocytes isolated from livers of rats with various models of acute uremia (binephrectomy, ureter ligation, uranyl nitrate-induced, or ischemic ARF) were incubated with glucagon, adrenalin, or cyclic AMP using serine as a substrate. A marked increase in glucose production was observed in the hepatocytes of uranyl nitrate-treated, binephrectomized, and ureter-ligated rats compared to starved controls or sham-operated animals. This effect was strengthened in the presence of glucagon, adrenaline, or cyclic AMP. In liver cells of binephrectomized and ureter-ligated animals, the production of acetoacetate and beta-hydroxybutyrate was significantly higher than in controls and sham-operated rats. Oxoglutarate and ATP production was only enhanced after ureter ligation. The correlation between glucose concentration and the cytosolic redox state was different in control and sham-operated rats than in either uremic group. This study confirms earlier investigations of a key role of serine in carbohydrate metabolism in acutely uremic rats.
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PMID:Effect of serine on gluconeogenic ability of hepatocytes in acute uremia. 633 Apr 26

Muscarinic cholinergic and adrenergic agonist-induced changes in [3H]-phosphatidyl inositol (PI) hydrolysis and cyclic AMP (cAMP) levels were measured in guinea pig ureter, urethra and bladder dome. In the ureter, carbachol, norepinephrine and phenylephrine rapidly increased PI hydrolysis and basal cAMP levels, but did not decrease forskolin-stimulated cAMP levels. In the bladder dome, norepinephrine and phenylephrine produced a rapid but transitory increase in PI hydrolysis, but did not affect forskolin-stimulated cAMP levels. Carbachol produced a rapid and sustained increase in PI hydrolysis and also, at high concentrations, decreased forskolin-stimulated cAMP levels. In the urethra, norepinephrine and carbachol rapidly decreased forskolin-stimulated cAMP levels and later increased PI hydrolysis. Our data suggest that the predominant second messenger system in the ureter, dome, or urethra is more dependent on the tissue than on the agonist. These tissue-specific, agonist-induced rapid changes in second messenger levels may help coordinate the contraction-relaxation phenomena necessary for urinary tract function.
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PMID:Effect of carbachol and norepinephrine on phosphatidyl inositol hydrolysis and cyclic AMP levels in guinea pig urinary tract. 775 91

Transport of K(+) by the lower, main and distal segments of the Malpighian tubules of Drosophila melanogaster was analyzed using self-referencing K(+)-selective microelectrodes. Transport properties of the Malpighian tubules of Drosophila melanogaster change along their length. Self-referencing ion-selective (SeRIS) microelectrode measurements (relative to the bath concentration of 20 mmoll(-1)) showed a 1% reduction (P<0.05) of [K(+)] in the unstirred layer adjacent to the main segment of the Malpighian tubules, confirming secretion of K(+) from the bath to the tubule lumen. Conversely, SeRIS measurements showed a 0.7% increase (P<0.05) in [K(+)] in the unstirred layer adjacent to the lower segment of Malpighian tubules, confirming reabsorption of K(+) from the luminal fluid to the bath. Measurements using SeRIS also showed that the distal segment neither secreted nor reabsorbed K(+). There was pronounced spatial heterogeneity in K(+) transport by the lower segment and the main segment; not all morphologically similar cells participated equally in K(+) transport, nor did all main segment cells respond equally to stimulation of K(+) transport by cyclic AMP. Pronounced temporal heterogeneity in K(+) reabsorption by the lower Malpighian tubules was also observed. We suggest that this reflects periodic reduction in K(+) reabsorption due to retention of fluid within the lower segment when the ureter contracts.
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PMID:Analysis of epithelial K(+) transport in Malpighian tubules of Drosophila melanogaster: evidence for spatial and temporal heterogeneity. 1150 12

We report a case of 2,8-dihydroxyadenine (DHA) urolithiasis in a 28-year old female. She was admitted to our hospital complaining of a sudden pain in the left lumbar region. Abdominal X-ray (kidney-ureter-bladder; KUB) and computed tomography (CT) demonstrated a radiolucent left ureteral (8 x 6 mm2) and a renal (15 x 10 mm2) stone. In the repetitive procedure of transurethral ureterolithothripsy (TUL) and extracorporeal shock wave lithotripsy (ESWL), the stones had been removed successfully. The spectrophotometric analysis of the stone fragments revealed an absorption spectrum for 2,8-DHA. Adenine phosphoribosyltransferase (APRT) enzyme activity was lowered to 0.8 nmol/hr/mg protein. Thus, we diagnosed the illness as 2,8-DHA urolithiasis originating from APRT deficiency. A molecular analysis of the APRT gene by the polymerase chain reaction (PCR) method revealed the genotype to be APRT*J/APRT*Q0.
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PMID:[2,8-dihydoroxyadenine (DHA) urolithiasis: a case report]. 1451 91

Cyclic nucleotide levels are controlled through their synthesis from nucleotide triphosphates by cyclases and their degradation to 5'-monophosphates by phosphodiesterases (PDEs). Components controlling cyclic AMP-induced relaxation in the urinary tract include receptors, inhibitory and stimulatory G-proteins, isoforms of adenylyl cyclase and PDEs. The responsiveness of PDEs to a variety of physiological challenges is related to the presence of multiple families of isoenzymes with specific localization within tissues and within cells. At least 11 families of PDEs encode more than 50 PDE proteins produced in mammalian cells. In the urinary tract, characterization of PDE isoforms has lagged behind other systems and much of the literature was published prior to identification of PDE7, 8, 9, 10, 11. Specific PDE inhibitors regulate smooth muscle function in the bladder, urethra, prostate and ureter. The pharmacological potential of these inhibitors may include treatment of urge incontinence and the low compliance bladder, and treatment of prostate cancer. G-proteins also regulate cyclic AMP production. Changes in specific G- protein isoforms with aging, most prominently Gialpha2, cause decreased relaxation response in the aging bladder. As we have seen here with aging and certainly in other disease processes, levels of the components of adenylyl cyclase/phosphodiesterase/protein kinase can change and thus affect the relaxation response. By exploitation of differences in PDE expression in disease, such as the overexpression of PDEs in cancer, treatment options may present themselves.
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PMID:Regulation of cyclic nucleotides in the urinary tract. 1585 36

Systemic administration of the potent vasodilating peptide adrenomedullin reduces cardiac and renal fibrosis in hypertensive animals. Here, we investigated the effects of kidney-specific adrenomedullin gene delivery in normotensive rats after unilateral ureteral obstruction, an established model of renal tubulointerstitial fibrosis. Overexpression of exogenous adrenomedullin in the renal interstitium following ureteral obstruction significantly prevented fibrosis and proliferation of tubular and interstitial cells. In this model, there is upregulation of connective tissue growth factor (CTGF) mRNA expression and extracellular signal-regulated kinase (ERK) phosphorylation, and adrenomedullin overexpression suppressed both of these activities without altering the blood pressure. In NRK-49F renal fibroblasts, adrenomedullin reduced transforming growth factor-beta-induced CTGF and fibronectin mRNA upregulation through the cyclic AMP/protein kinase A signaling pathway, and suppressed ERK phosphorylation and cell proliferation. In the kidneys with an obstructed ureter, adrenomedullin receptor gene expression was upregulated along with cyclic AMP production in kidney slices. The latter effect was partially blocked by a neutralizing antibody to adrenomedullin, indicating that an endogenous peptide-receptor system was activated. Our results show that overexpression of exogenous adrenomedullin in the ureteral-obstructed kidney prevents tubulointerstitial fibrosis and cell proliferation through the cyclic AMP-mediated decrease of CTGF induction and ERK phosphorylation.
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PMID:Adrenomedullin inhibits connective tissue growth factor expression, extracellular signal-regulated kinase activation and renal fibrosis. 1840 34


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