Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activities of enzymes related to the cellular action of vasopressin as well as the activities of other enzymes were studied in an animal model of hypothalamic diabetes insipidus. Rats with hereditary hypothalamic diabetes insipidus (homozygotes of Bratteboro strain) were found to have significantly lower renal medullary adenylate cyclase activity, either basal activity or activity stimulated by vasopressin, as compared with controls (heterozygotes of the same strain). There were no differences between the two strains in the activities of cyclic AMP phosphodiesterase, other hormone-sensitive adenylate cyclases, or the other renal medullary enzymes studied, which are apparently unrelated to the vasopressin action. The treatment of rats with hereditary hypothalamic diabetes insipidus with exogenous vasopressin increased the activity of renal medullary adenylate cyclase stimulated in vitro by maximal doses of vasopressin, but had no effect on the basal activity of adenylate cyclase or on the activity of cyclic AMP phosphodiesterase. This suggests that low adenylate cyclase activity in the renal medulla of rats with diabetes insipidus may be related to the subnormal concentrating ability observed in these animals.
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PMID:Renal medullary adenylate cyclase in rats with hypothalamic diabetes insipidus. 17 17

In a previous study we demonstrated that indomethacin potentiated the hydro-osmotic action of vasopressin in vivo. It was hypothesized that this action of indomethacin was due to its ability to suppress renal medullary prostaglandin synthesis, since in vitro studies have suggested that prostaglandins interfere with the ability of vasopressin to stimulate production of its intracellular mediator, cyclic AMP. In the present study this hypothesis was tested in vivo. Anesthetized rats undergoing a water diuresis were studied. In a control group, bolus injections of 200 muU of vasopressin caused a rise in urinary osmolality (Uosm) from 124 +/- 6 to 253 +/- 20 mosmol/kg H2O (P less than 0.005). In a group treated with 2 mg/kg of indomethacin the same dose of vasopressin caused a significantly greater (P less than 0.001) rise in Uosm from 124 +/- 7 to 428 +/- 19 mosmol/kg H2O. Medullary tissue cyclic AMP rose from 9.4 +/- 0.9 to 13.4 +/- 1.7 (P less than 0.05) pmol/mg tissue protein after vasopressin administration in animals receiving no indomethacin, while in indomethacin-treated animals there was a significantly greater rise (P less than 0.001) in medullary cyclic AMP from 10.4 +/- 0.9 to 21.6 +/- 2.1 pmol/mg tissue protein in response to the vasopressin injections. In neither control animals nor indomethacin-treated animals were there significant changes in renal hemodynamics, as measured by clearance techniques. Indomethacin, when given alone, had no effect on Uosm or medullary tissue cyclic AMP. Indomethacin did, however, reduce medullary prostaglandin E content from 84.7 +/- 15.0 to 15.6 +/- 4.3 pg/mg tissue. This study has shown that indomethacin, in a dose which suppresses medullary prostaglandin content, potentiates the ability of vasopressin to increase the tissue content of its intracellular mediator, cyclic AMP. Indomethacin caused no demonstrable inhibition of cyclic AMP phosphodiesterase. Therefore, it seems likely that indomethacin enhanced the ability of vasopressin to increase medullary cyclic AMP levels by causing an increased production rather than decreased destruction of the nucleotide. We conclude that this action of indomethacin contributes to its ability to potentiate the hydro-osmotic action of vasopressin in vivo. A corollary to this conclusion is that endogenous medullary prostaglandin E's may be significant physiological modulators of the renal response to vasopressin.
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PMID:In vivo effect of indomethacin to potentiate the renal medullary cyclic AMP response to vasopressin. 18 24

1. The effects of adrenalectomy on the adenylate cyclase--adenosine 3':5'-cyclic monophosphate (cyclic AMP) system of rat renal medulla were examined to evaluate the mechanism of the impaired water diuresis in glucocorticoid deficiency. 2. Concentrations of cyclic AMP in medullary tubules from adrenalectomized rats were significantly higher than in the tubules from control animals both in the presence and absence of antidiuretic hormone. 3. This abnormality was corrected by the treatment in vivo of the adrenalectomized rats with dexamethasone, but addition of this drug to the incubation medium did not abolish the differences in cyclic AMP between tubules from adrenalectomized and normal rats. 4. The activity of adenylate cyclase or cyclic AMP phosphodiesterase in vitro was not affected by adrenalectomy. 5. In glucocorticoid deficiency, the concentration of cyclic AMP in medullary tubules is increased both with and without antidiuretic hormone. This abnormality may render medullary tubules more permeable to water and may underlie the impaired water diuresis in glucocorticoid deficiency.
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PMID:Effects of glucocorticoid deficiency on renal medullary cyclic adenosine monophosphate of rats. 21 86

In experiments on frog urinary bladder the mechanisms behind the gradual development of a hydroosmotic reaction to antidiuretic hormone (ADH) were investigated. It was suggested that the velocity of hydroosmotic reaction may be limited by (a) formation and insertion of particle aggregates into the apical membrane or (b) by velocity of cAMP formation. The urinary bladders were exposed to 23 nM ADH for different times (from 1 to 20 min) and water flow was measured over a period of 40 min. It was found that the value of the full hydroosmotic response increased progressively with the time of exposure to the hormone; however, the enhancement of water flow was equal during each time interval before reaching the reaction maximum. A direct correlation between the value of ADH-stimulated water flow, cAMP content in bladder tissue and frequency of particle aggregates in the granular cell apical membrane was observed. The content of cAMP in ADH-treated bladders was higher by 80% in the absence than in the presence of an osmotic gradient. Pretreatment of urinary bladders with 50 microM cyclic nucleotide phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine, significantly accelerated the development of the hydroosmotic reaction and increased the magnitude of water flow in comparison with the effect of ADH only. No changes in cyclic AMP phosphodiesterase activity were found in the urinary bladder homogenates under the action of ADH, so it seems likely that accumulation of cAMP depends only on the increase of adenylate cyclase activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Does the gradual hydroosmotic response to antidiuretic hormone depend on intracellular cAMP accumulation or on the formation of intramembrane particle aggregates? 127 17

The mechanism whereby glucagon causes an increase in the concentration of cytoplasmic free Ca2+, [Ca2+]c, in isolated hepatocytes has been investigated. There have been proposals of cyclic-AMP-dependent and cyclic-AMP-independent mechanisms. In this work, the inactivation of pyruvate kinase was used as an indicator of increases in the activity of cyclic-AMP-dependent protein kinase, A-kinase. [Ca2+]c was measured using the fluorescent probe indo-1. The decrease in activity of pyruvate kinase caused by an increase in [Ca2+]c alone, i.e. mediated by mechanisms not involving cyclic AMP and exemplified by the effect of vasopressin, was of minimal significance under the conditions of the enzyme assay. Studies of the effects of a wide range of glucagon concentrations indicate that any increase in [Ca2+]c caused by glucagon was always associated with a decrease in pyruvate kinase activity. A similar relationship was obtained if glucagon-receptor occupancy was circumvented by using the 8-bromo-derivative of cyclic AMP to activate the A-kinase. It was also found that the cyclic AMP phosphodiesterase inhibitor isobutylmethylxanthine could potentiate the ability of glucagon to increase [Ca2+]c: no such potentiation was observed when vasopressin was used to raise [Ca2+]c. Together these data indicate that an increase in cyclic AMP concentration, sufficiently great to activate A-kinase, is a mechanism that mediates the glucagon-induced increase in [Ca2+]c.
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PMID:Evidence indicating that the glucagon-induced increase in cytoplasmic free Ca2+ concentration in hepatocytes is mediated by an increase in cyclic AMP concentration. 253 1

Treatment of intact adipocytes with either or both insulin and adrenaline stimulated membrane cyclic AMP phosphodiesterase activity only in the endoplasmic reticulum subfraction. The cyclic GMP-inhibited cyclic AMP phosphodiesterase activity was also found in this fraction. Quantitative Western blotting using a specific polyclonal antibody, raised against the homogeneous 'dense-vesicle' cyclic AMP phosphodiesterase from rat liver, identified a single 63 kDa species which was localized in the adipocyte endoplasmic reticulum fraction. The ability of adrenaline to stimulate adipocyte membrane cyclic AMP phosphodiesterase was shown to be mediated via beta-adrenoceptors and not alpha 1-adrenoceptors. Membrane cyclic AMP phosphodiesterase was stimulated by glucagon but not by vasopressin, A23187 or 12-O-tetradecanoylphorbol 13-acetate (TPA). Treatment of adipocytes with either chloroquine or dansyl cadaverine failed to affect the ability of insulin to stimulate cyclic AMP phosphodiesterase activity. Treatment of an isolated adipocyte endoplasmic reticulum membrane fraction with purified protein kinase A increased its cyclic AMP phosphodiesterase activity some 2-fold. When this fraction was treated with purified protein kinase A and [32P]ATP, label was incorporated into a 63 kDa protein which was specifically immunoprecipitated with the antiserum against the liver 'dense-vesicle' cyclic AMP phosphodiesterase.
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PMID:Subcellular localization and hormone sensitivity of adipocyte cyclic AMP phosphodiesterase. 255 12

To evaluate the possible role of microtubules in the cellular action of vasopressin on the mammalian kidney, the effects of microtubule-disrupting agents were studied in vivo and in vitro. In vivo studies were done in rats in mild to moderate water diuresis induced by drinking 5% glucose. Microtubule-disrupting alkaloids, colchicine (0.1 mg/day) or vinblastine (0.08 mg/day), given intraperitoneally, did not change water and solute excretion itself, but blocked or markedly inhibited the antidiuretic response (increase in urine osmolality and decrease in urine flow) to exogenous vasopressin. Total solute excretion was unaffected by these two alkaloids and there were no substantial changes in excretion of sodium, potassium, or creatinine. Lumicolchicine, a derivative of colchicine that does not interact with microtubules, did not alter the antidiuretic response to exogenous vasopressin. Activities of adenylate cyclase in the renal medullary plasma membrane, and cyclic AMP phosphodiesterase and protein kinase in renal medullary cytosol, were not influenced by 10(-5)-10(-4) M colchicine or vinblastine in vitro. Studies on the subcellular distribution of microtubular protein (assessed as [(3)H]colchicine-binding protein) in renal medulla shows that this protein is contained predominantly in the cytosol. Particulate fractions, including plasma membrane, contain only a minute amount (less than 6%) of the colchicine-binding activity. The results suggest that the integrity of cytoplasmic microtubules in cells of the distal nephron is required for the antidiuretic action of vasopressin, probably in the sites distal to cyclic AMP generation in the mammalian kidney.
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PMID:Effects of colchicine and vinblastine on the cellular action of vasopressin in mammalian kidney. A possible role of microtubules. 436 87

Previous work has suggested that resistance to vasopressin in two strains of mice with nephrogenic deficiency of urinary concentration may entail a defect in the action of vasopressin at the cellular level. Several components involved in this action were therefore examined in vitro in renal medullary tissues from control mice (genotype VII +/+) and two genotypes with mild diabetes insipidus (DI +/+ nonsevere) and marked (DI +/+ severe) vasopressin-resistant concentrating defects. No significant differences were found in the affinity of adenylate cyclase for [8-arginine]-vasopressin (AVP), tested over a range of hormone concentration from 10(-10) to 10(-5) M. However, maximal stimulation of adenylate cyclase by saturating concentrations of AVP (intrinsic activity) was markedly decreased from control values in DI +/+ severe mice, and decreased to a lesser extent in DI +/+ nonsevere animals. A significant correlation was found between the activity of adenylate cyclase maximally stimulated by AVP in a given genotype, and the urine osmolality in the same animals. There were no significant differences in maximal stimulation of renal medullary adenylate cyclase in control experiments: not when stimulated nonspecifically by sodium fluoride, nor when stimulated by AVP in tissues from rats with induced water diuresis as compared to antidiuretic rats. Nor were there significant differences between VII +/+ and DI +/+ severe mice in the activity of renal cortical adenylate cyclase, either basal or when stimulated by parathyroid hormone. Furthermore, the abnormal genotypes did not differ significantly from control mice in the renal medullary activities of cyclic AMP phosphodiesterase or cyclic AMP-dependent protein kinase, nor in the content of microtubular subunits (assessed as colchicinebinding protein). The results are compatible with the view that impaired stimulation of renal medullary adenylate cyclase by vasopressin might be the sole or contributing cause of the vasopressin-resistant concentrating defect in the diseased mice; however, a causal relationship has not yet been proved.
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PMID:Cellular action of antidiuretic hormone in mice with inherited vasopressin-resistant urinary concentrating defects. 436 80

Mineralo- and glucocorticoid-deficient states, such as Addison's disease, are partly characterized by an inability to generate a maximally concentrated urine. The purpose of the present study was to develop a model of adrenal insufficiency and to determine whether changes in the intrinsic function of the collecting duct could partly account for this concentrating defect. Two kinds of experiments were performed: an assessment of the in vivo ability of adrenal-ectomized rabbits to concentrate their urine, and an examination of the intrinsic hydroosmotic responsiveness of in vitro perfused collecting ducts isolated from normal and adrenalectomized rabbits. The present study demonstrates that adrenalectomized rabbits are unable to concentrate their urine maximally, and that the in vivo administration of either deoxycorticosterone, 250 mug/kg, or dexamethasone, 50 mug/kg, restored to or toward normal their concentrating ability. When cortical collecting tubules from adrenalectomized rabbits were perfused in vitro, they demonstrated a markedly blunted hydroosmotic response to antidiuretic hormone (ADH), which was corrected by the in vitro addition of either aldosterone (50 pM) or dexamethasone (50 pM), but not progesterone (50 pM). The steroids by themselves, in the absence of ADH, had no intrinsic effect on the water permeability of the collecting duct. The blunted hydroosmotic response across cortical collecting tubules from adrenal-ectomized rabbits was corrected by the addition of either 8-bromo cyclic AMP or a potent phosphodiesterase inhibitor, 1-methyl-3-isobutylxanthine. The present studies show that the cortical collecting tubules obtained from adrenalectomized rabbits do not respond normally to ADH. The poor hydroosmotic response to ADH was corrected by exogenous aldosterone, dexamethasone, an analog of cyclic AMP, or a phosphodiesterase inhibitor. In conclusion, the present studies are consistent with the view that the concentrating defect seen in adrenal insufficiency is at least partly the result of the absence of the permissive effect that adrenal steroids exert on the ADH-induced reabsorption of water across the collecting duct. The absence of adrenal steroids results in a diminished rate of cyclic AMP accumulation in the cells of the collecting duct, either as a result of an augmented activity of cyclic AMP phosphodiesterase or a diminished rate of cyclic AMP generation.
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PMID:Urinary concentrating defect of adrenal insufficiency. Permissive role of adrenal steroids on the hydroosmotic response across the rabbit cortical collecting tubule. 615 51

Amrinone is a new noncatechol, nonglycoside agent with cardiotonic and vasodilator properties. This paper examines the effects of amrinone in the toad urinary bladder, a tissue whose function may be altered by many factors which also change cardiovascular activity. Amrinone enhanced the effect of vasopressin and cyclic AMP on water and urea permeabilities, as well as the effect of vasopressin on sodium transport. Consistent with these actions, amrinone inhibited cyclic AMP phosphodiesterase activity in epithelial homogenates and increased both cyclic AMP content and the protein kinase activity ratio measured in intact epithelial cells. The inhibitory effect of amrinone on phosphodiesterase may be relevant to its cardiostimulatory and vasodilator activities.
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PMID:The effects of amrinone on transport and cyclic AMP metabolism in toad urinary bladder. 625 81


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