Publications by authors named "Braun-Werness J"

In mice with hereditary nephrogenic diabetes insipidus (NDI), the high activity of cAMP-phosphodiesterase (cAMP-PDIE) in medullary collecting tubules (MCT) prevents the increase in cAMP content in response to vasopressin [Arg8]vasopressin (AVP). Even when the cAMP response to AVP is partly corrected by cAMP-PDIE inhibitor 1-methyl-3-isobutylxanthine (MIX), under all tested conditions the cAMP levels in MCT of NDI mice remained much lower than in controls (B. A.

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Responsiveness of proximal convoluted tubule (PCT) and distal convoluted tubule (DCT) microdissected from mouse kidney to PTH, in terms of cAMP accumulation and stimulation of adenylate cyclase, was examined. In both PCT and DCT, the cell-free adenylate cyclase was stimulated at least 10-fold by the same dose (10 U/ml) of PTH, and activity of cAMP phosphodiesterase was about 80% higher in DCT than in PCT. In intact tubules, while the incubation with PTH increased cAMP content in DCT more than 10-fold, it failed to increase the cAMP levels in PCT.

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To determine vasopressin (VP)-potentiating effect of chlorpropamide (CPMD), we studied the effect of CPMD in vivo and in vitro in kidneys and in specific tubule segments of rats with hypothalamic diabetes insipidus, homozygotes of the Brattleboro strain (DI rats). Rats on ad lib. water intake were treated with CPMD (20 mg/100 g body wt s.

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Among other defects in water metabolism, adrenal insufficiency is associated with an inability to concentrate urine maximally in both man and experimental animals. Recent studies in the rabbit cortical collecting tubule have suggested indirectly that this defect may result from impaired cyclic AMP (cAMP) formation in response to antidiuretic hormone stimulation. In the present study, we examined key elements of arginine vasopressin (AVP)-dependent cAMP metabolism in the papillary collecting duct (PCD), microdissected from 8-d adrenalectomized (ADX) and sham-operated control rats.

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The characteristics of nicotinamide adenine dinucleotide (NAD) binding on brush border membranes prepared from rat renal cortex were investigated with the use of radioactively labelled NAD, [adenine-2,8-3H]NAD+, as a ligand. (1) We found that NAD binds on brush border membrane and that the extent of NAD binding is linearly proportional to the brush border membrane protein, and progressively increases with concentration of NAD in the medium. (2) The rate of NAD binding was dependent on temperature.

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