Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.4.1 (phosphodiesterase)
 18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of chlorpropamide was determined in Brattleboro diabetes insipidus (DI) rats that were injected with 1-deamino-8-D-arginine vasopressin (dDAVP). Chlorpropamide augmented the antidiuretic responses to 0.78 and 1.56 ng dDAVP but not to larger doses. In an effort to explain this observation we investigated the effect of chlorpropamide on renal medullary adenylate cyclase activation by dDAVP and on phosphodiesterase activity. We found that the injection of chlorpropamide increased adenylate cyclase activation by dDAVP added in vitro to renal medullary cell membrane preparations from Brattleboro DI rats but had no effect on phosphodiesterase activity. When kidneys from Brattleboro DI rats, treated and not treated with chlorpropamide, were perfused in vitro, we found that 10(-4) M dDAVP increased the concentration of cAMP in comparison to untreated and chlorpropamide-treated groups, and that chlorpropamide plus dDAVP resulted in a greater concentration of renal cAMP than was found with dDAVP alone. We believe that treatment with chlorpropamide increases dDAVP-stimulated renal medullary adenylate cyclase activity without altering phosphodiesterase activity and that this leads to increased renal cAMP concentrations. This, in turn, causes an augmented antidiuresis in response to dDAVP.
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PMID:Augmentation by chlorpropamide of 1-deamino-8-D-arginine vasopressin-induced antidiuresis and stimulation of renal medullary adenylate cyclase and accumulation of adenosine 3',5'-monophosphate. 624 58

Previously, we demonstrated that escape from vasopressin-induced antidiuresis ("vasopressin escape") in rats is associated with a large, selective decrease in whole kidney expression of aquaporin-2, the vasopressin-regulated water channel. Here, we show that isolated perfused inner medullary collecting ducts (IMCDs) from vasopressin-escape rats desamino-[D-arginine]vasopressin (DDAVP)/water-loaded have dramatically reduced vasopressin-dependent osmotic water permeabilities [46% of control rats (DDAVP alone)], which coincides with a fall in inner medullary aquaporin-2 protein abundance as measured by immunoblotting in the opposite kidney. Furthermore, we demonstrate in IMCD suspensions that cAMP accumulation in response to DDAVP is substantially reduced in the vasopressin-escape rats both in the presence and absence of the phosphodiesterase inhibitor IBMX. By immunoblotting, we show that the abundance of two proteins important in cAMP generation: the stimulatory heterotrimeric G protein subunit Gs and adenylyl cyclase type VI, do not change. We conclude that vasopressin escape is associated with relative vasopressin resistance of the collecting duct cells manifested by decreased intracellular cAMP levels. The decreased cAMP levels can contribute to the demonstrated decrease in collecting duct water permeability in two ways: 1) by causing a decrease in aquaporin-2 expression and 2) by limiting the acute action of vasopressin to increase collecting duct water permeability.
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PMID:Escape from vasopressin-induced antidiuresis: role of vasopressin resistance of the collecting duct. 984 9