The objective of this proposal is to examine the biochemical mechanisms of renal resistance to vasopressin (AVP) in two settings associated with nephrogenic diabetes insipidus (NDI): administration of pharmacologic agents (lithium and demeclocycline) that are known to cause a renal concentrating defect and congenital NDI. The system in which studies will be performed is a primary culture of inner medullary collecting tubule cells that responds specifically to AVP by forming the intermediate effector of the hormone's action, cAMP, in a dose dependent manner. Vasopressin-stimulated cAMP formation will be determined in the presence and absence of phosphodiesterase inhibition. Prostaglandin E2 production in these settings will be measured and the effect of prostaglandin synthesis inhibitors on cAMP production will be assessed. The site of the receptor-adenylate cyclase complex at which any changes occur will be defined. A binding assay will examine receptor function and forskolin will be employed to directly stimulate the catalytic unit. Studies directed at assessing whether a guanine nucleotide binding regulatory subunit defect is operant will employ agents (e.g. cholera toxin, pertussis toxin) known to stimulate at this site. In conjunction with these latter studies an adenylate cyclase complementation assay employing the cyc- mutant of murine S49 lymphoma cells will be performed. These studies will significantly enhance our understanding of the biochemical mechanisms that underly commonly encountered AVP resistant states characterized clinically by polyuria, polydipsia and impaired urinary concentration.

Project Start
1986-08-01
Project End
1992-01-31
Budget Start
1990-08-01
Budget End
1992-01-31
Support Year
5
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Colorado Denver
Department
Type
Schools of Medicine
DUNS #
065391526
City
Aurora
State
CO
Country
United States
Zip Code
80045
Teitelbaum, I; Berl, T (1994) Increased cytosolic Ca2+ inhibits AVP-stimulated adenylyl cyclase activity in rat IMCT cells by activation of PKC. Am J Physiol 266:F486-90
Heasley, L E; Senkfor, S I; Winitz, S et al. (1994) Hormonal regulation of MAP kinase in cultured rat inner medullary collecting tubule cells. Am J Physiol 267:F366-73
Teitelbaum, I (1993) Protein kinase C inhibits arginine vasopressin-stimulated cAMP accumulation via a Gi-dependent mechanism. Am J Physiol 264:F216-20
Teitelbaum, I (1992) Hormone signaling systems in inner medullary collecting ducts. Am J Physiol 263:F985-90
Teitelbaum, I (1991) Vasopressin-stimulated phosphoinositide hydrolysis in cultured rat inner medullary collecting duct cells is mediated by the oxytocin receptor. J Clin Invest 87:2122-6
Teitelbaum, I; Strasheim, A; Berl, T (1990) Epidermal growth factor-stimulated phosphoinositide hydrolysis in cultured rat inner medullary collecting tubule cells. Regulation by G protein, calcium, and protein kinase C. J Clin Invest 85:1044-50
Teitelbaum, I (1990) Cyclic adenosine monophosphate and diacylglycerol. Mutually inhibitory second messengers in cultured rat inner medullary collecting duct cells. J Clin Invest 86:46-51
Teitelbaum, I (1990) The epidermal growth factor receptor is coupled to a phospholipase A2-specific pertussis toxin-inhibitable guanine nucleotide-binding regulatory protein in cultured rat inner medullary collecting tubule cells. J Biol Chem 265:4218-22
Teitelbaum, I; Strasheim, A (1990) AVP stimulates adenylyl cyclase and phospholipase C in reciprocal fashion in cultured RIMCT cells. Am J Physiol 259:C693-6
Teitelbaum, I; Strasheim, A; Berl, T (1989) Adrenergic control of cAMP generation in rat inner medullary collecting tubule cells. Kidney Int 35:647-53