Pump-Leak Coupling in the Amphibian Diluting Segment

1994 ◽  
Vol 17 (3-4) ◽  
pp. 138-142
Author(s):  
Gordon Cooper ◽  
Annette Hurst ◽  
Paul Lynch ◽  
Malcolm Hunter
Keyword(s):  
Diluting Segment

Suppressed Diluting Segment Reabsorption in Bartter’s Syndrome: Studies in 1 Patient and Synthesis of Literature Data

1988 ◽  
Vol 8 (5) ◽  
pp. 402-409 ◽  
Author(s):  
Ronald J. Hené ◽  
Hein A. Koomans ◽  
Evert J. Dorhout Mees
Keyword(s):  
Diluting Segment

Role of distal delivery of filtrate in impaired renal dilution of the hypothyroid rat

1976 ◽  
Vol 230 (3) ◽  
pp. 699-705 ◽  
Author(s):  
UF Michael ◽  
J Kelley ◽  
H Alpert ◽  
CA Vaamonde
Keyword(s):  
Free Water ◽  
Urine Flow ◽  
Distal Nephron ◽  
Sprague Dawley ◽  
Diluting Segment ◽  
Free Water Clearance ◽  
Sprague Dawley Rats ◽  
And Control ◽  
Distal Delivery

Free water clearance (CH2O) was measured during hypotonic saline infusion in Sprague-Dawley and in Brattleboro (DI) rats with 131I-induced hypothyroidism and their age-matched controls. At peak urine flow, which was similar in hypothyroid DI (HDI) and control DI (CDI) rats, inulin clearance (CIn/kg) and CH2O/kg were 23 and 20% (P less than 0.02) lower in HDI. Fractional urine flow and fractional sodium excretion were 30 and 40% (P less than 0.001) higher in HDI. Utilization of distal delivery of filtrate for CH2O, formation was 16% less in HDI (P less than 0.01). Papillary osmolality was not higher in HDI rats. Data in Sprague-Dawley rats were similar to those of the DI rats, indicating that endogenous ADH was effectively suppressed. It is concluded: 1) delivery of filtrate out of the proximal tubule was not diminished in hypothyroid rats in spite of a decrease in CIn; 2) despite a similar delivery of filtrate to the distal diluting site, CH2O formation was less in hypothyroid rats than in controls; 3) these data suggest that a defect in the diluting segment could be unmasked at high rates of filtrate delivered to the distal nephron; 4) this defect could be either due to impaired sodium chloride reabsorption or due to increased backdiffusion of water in the distal nephron.

Evidence for an amiloride sensitive Na+ pathway in the amphibian diluting segment induced by K+ adaptation

1983 ◽  
Vol 399 (3) ◽  
pp. 166-172 ◽  
Author(s):  
Hans Oberleithner ◽  
Florian Lang ◽  
Wenhui Wang ◽  
Georg Messner ◽  
Peter Deetjen
Keyword(s):  
Diluting Segment

scholarly journals Expression of a novel isoform of Na+/H+ exchanger 3 in the kidney and intestine of banded houndshark, Triakis scyllium

2013 ◽  
Vol 304 (10) ◽  
pp. R865-R876 ◽  
Author(s):  
Shanshan Li ◽  
Akira Kato ◽  
Souichirou Takabe ◽  
An-Ping Chen ◽  
Michael F. Romero ◽  
...  
Keyword(s):  
Apical Membrane ◽  
Single Gene ◽  
Acid Base ◽  
Spiral Intestine ◽  
Diluting Segment ◽  
Aquatic Vertebrates ◽  
Promoter Usage ◽  
Distal Tubules ◽  
Immunohistochemical Analyses

Na+/H+ exchanger 3 (NHE3) provides one of the major Na+ absorptive pathways of the intestine and kidney in mammals, and recent studies of aquatic vertebrates (teleosts and elasmobranchs) have demonstrated that NHE3 is expressed in the gill and plays important roles in ion and acid-base regulation. To understand the role of NHE3 in elasmobranch osmoregulatory organs, we analyzed renal and intestinal expressions and localizations of NHE3 in a marine elasmobranch, Japanese banded houndshark ( Triakis scyllium). mRNA for Triakis NHE3 was most highly expressed in the gill, kidney, spiral intestine, and rectum. The kidney and intestine expressed a transcriptional isoform of NHE3 (NHE3k/i), which has a different amino terminus compared with that of NHE3 isolated from the gill (NHE3g), suggesting that NHE3k/i and NHE3g arise from a single gene by alternative promoter usage. Immunohistochemical analyses of the Triakis kidney demonstrated that NHE3k/i is expressed in the apical membrane of a part of the proximal and late distal tubules in the sinus zone. In the bundle zone of the kidney, NHE3k/i was expressed in the apical membrane of the early distal tubules known as the diluting segment. In the spiral intestine and rectum, NHE3k/i was localized toward the apical membrane of the epithelial cells. The transcriptional levels of NHE3k/i were increased in the kidney when Triakis was acclimated in 130% seawater, whereas those in the spiral intestine were increased in fish acclimated in diluted seawater. These results suggest that NHE3 is involved in renal Na+ reabsorption, urine acidification, and intestinal Na+ absorption in elasmobranchs.

Studies on Mineralocorticoid ‘Escape’ in Cirrhosis

1979 ◽  
Vol 56 (5) ◽  
pp. 401-406 ◽  
Author(s):  
S. P. Wilkinson ◽  
I. K. Smith ◽  
Helen Moodie ◽  
Lucilla Poston ◽  
R. Williams
Keyword(s):  
Extracellular Fluid ◽  
Plasma Renin ◽  
Fluid Volume ◽  
The Other ◽  
Extracellular Fluid Volume ◽  
Sodium Reabsorption ◽  
Sodium Retention ◽  
Similar Extent ◽  
Water Diuresis ◽  
Diluting Segment

1. The mineralocorticoid 9α-fluorohydrocortisone was given to 12 patients with cirrhosis without ascites. In seven an ‘escape’ from its sodium-retaining effects was observed, the other five continuing to retain sodium. 2. Changes in plasma renin activity (PRA) and inulin clearance (Cinulin) were used in the assessment of possible changes in the ‘effective’ extracellular fluid volume. PRA fell and Cinulin increased to a similar extent in each of the two groups of patients. These findings do not support the concept that the failure to show the mineralocorticoid escape in some patients with cirrhosis is due to a failure of expansion of the effective extracellular fluid volume. 3. Sodium reabsorption in the different segments of the nephron as estimated by clearance techniques under conditions of maximal water diuresis showed that the greatest changes to account for both mineralocorticoid escape and sodium retention were in the part of the nephron beyond the diluting segment.

Role of Antidiuretic Hormone in Impaired Urinary Dilution Associated with Chronic Bile-Duct Ligation

1980 ◽  
Vol 58 (6) ◽  
pp. 493-500 ◽  
Author(s):  
O. S. Better ◽  
G. A. Aisenbrey ◽  
T. Berl ◽  
R. J. Anderson ◽  
W. A. Handelman ◽  
...  
Keyword(s):  
Bile Duct ◽  
Antidiuretic Hormone ◽  
Bile Duct Ligation ◽  
Diluting Segment ◽  
Water Excretion ◽  
Duct Ligation ◽  
Normal Mean ◽  
And Function ◽  
Distal Delivery

1. The effect of chronic bile-duct ligation on systemic and renal haemodynamics and on the capacity to dilute the urine was studied in conscious rats. Sham-operated rats served as controls. 2. In the rats with bile-duct ligation, the maximal urinary diluting capacity was impaired, despite an expanded plasma volume, a normal mean arterial pressure and cardiac output, and normal intrarenal determinants of water excretion including distal delivery of fluid and function of the diluting segment. 3. In contrast, maximal urinary dilution capacity was intact in rats with congenital central diabetes insipidus and chronic bile-duct ligation. 4. It is concluded that the defect in urinary dilution in rats with chronic bile-duct ligation is dependent on antidiuretic hormone.

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