CLEARANCE- UND STOP-FLOW-UNTERSUCHUNGEN AN INTAKTEN UND DIABETES-INSIPIDUS-RATTEN IN WASSER- UND OSMOTISCHER DIURESE OHNE UND MIT ZUFUHR EXOGENEN VASOPRESSINS

1966 ◽  
Vol 52 (2) ◽  
pp. 239-254 ◽  
Author(s):  
Günther Vogel ◽  
Ingrid Stoeckert ◽  
Ruth Winkler
Keyword(s):  
Diabetes Insipidus ◽  
Electrolyte Concentration ◽  
Free Water ◽  
Free Flow ◽  
Water Diuresis ◽  
Osmotic Diuresis ◽  
Free Water Clearance ◽  
Stop Flow ◽  
Ureteral Occlusion ◽  
Concentration Patterns

ABSTRACT To clarify the significance of vasopressin on various parameters of renal function, clearance and »stop-flow« tests on intact rats and those with induced diabetes insipidus were carried out during water and osmotic (mannitol) diuresis. With regard to renal clearance, urinary concentration and renal output, water diuresis in the intact and diabetic insipidus rats was the same: low urine osmolarity, low electrolyte concentration, positive free water clearance and low rate of electrolyte excretion. The concentration patterns taken 3 minutes after ureteral occlusion showed for Na+ and Cl−: low free flow values and proximal maximum; osmolarity: low free flow values with a distal maximum below the plasma concentration; creatinine: distal maximum; urea: high free flow values with distal maximum. In the osmotic diuresis of intact animals, the electrolyte concentration was substantially higher; correspondingly, excretory output was much increased as compared to water diuresis, with negative free water clearance. The »stop-flow« patterns for Na+ and Cl− – starting with 70–100 mmol/l – showed a distal minimum, for osmolarity a distal maximum; and the same for creatinine and urea. The measured parameters obtained from diabetic insipidus animals in osmotic diuresis showed a marked approximation – up to equivalence – to that of intact and diabetic insipidus animals in water diuresis. When diabetes insipidus animals in osmotic diuresis were administered arginine-vasopressin as a continuous infusion, the results completely matched those of the measured parameters in the osmotic diuresis of intact animals. The importance of vasopressin on renal transports can thus be demonstrated not only by clearance and excretory tests, but also by the concentration patterns after ureteral occlusion.

Free water excretion in normal dogs

1962 ◽  
Vol 202 (6) ◽  
pp. 1131-1135 ◽  
Author(s):  
E. Lovell Becker ◽  
H. Earl Ginn
Keyword(s):  
Sodium Chloride ◽  
Sodium Sulfate ◽  
Free Water ◽  
Maximal Rate ◽  
Water Diuresis ◽  
Osmotic Diuresis ◽  
Free Water Clearance ◽  
Water Excretion ◽  
Early Increase ◽  
Water Clearance

Free water excretion (Chh2o = V - Cosm) was studied in unanesthetized dogs. This parameter of urine dilution was defined by superimposing an osmotic diuresis upon a water diuresis. Sodium sulfate (1.5%) gave the smallest free water clearance and sodium chloride (0.95%) the greatest, urea (1.65%) and mannitol (5.0%) being intermediary in their effects. Observed free water clearances were never maximal and, when plotted as Cosm vs. V, gave a slope of less than one. Two mercurial diuretics, meralluride and mercaptomerin, gave intermediary values for free water. Meralluride caused an early increase in free water clearance because of the theophylline incorporated in the compound. Later results were similar to those with mercaptomerin, both compounds producing free water clearances approaching a maximal rate.

Mechanism of Action of Indomethacin in Tubular Defects

PEDIATRICS ◽  
1985 ◽  
Vol 75 (3) ◽  
pp. 501-507
Author(s):  
Mario Usberti ◽  
Carmine Pecoraro ◽  
Stefano Federico ◽  
Bruno Cianciaruso ◽  
Bruna Guida ◽  
...  
Keyword(s):  
Prostaglandin E2 ◽  
Diabetes Insipidus ◽  
Mechanism Of Action ◽  
Nephrogenic Diabetes Insipidus ◽  
Fanconi Syndrome ◽  
Free Water ◽  
Synthesis Inhibitor ◽  
Free Water Clearance ◽  
Water Excretion ◽  
Water Load

Indomethacin, a potent prostaglandin synthesis inhibitor, has been proven to be effective in a number of tubular defects characterized by enhanced prostaglandin (namely, prostaglandin E2 (PGE2) production, but its mechanism of action is poorly understood. To elucidate further the mechanism(s) by which indomethacin reverses the abnormal tubular functions, five children with different tubular defects (nephrogenic diabetes insipidus, three cases; Fanconi syndrome, one case; and pseudohypoaldosteronism, one case) were treated with indomethacin. Indomethacin, 1 mg/kg every eight hours, was given for 1 week to all children and then was given chronically to four of the children who responded to the drug. Its use was suspended in a 10 year-old-boy with nephrogenic diabetes insipidus because it proved ineffective. To assess the site along the nephron where indomethacin affects the solute and water excretion, an acute water load study was performed in three responsive children before and during the treatment. Indomethacin did not significantly alter the glomerular filtration rate but was effective in reducing diuresis and levels of urinary sodium and potassium excretion. In the child with Fanconi syndrome, indomethacin was also effective in controlling the urinary loss of phosphate, urate, glucose, and bicarbonate. Results of the water load studies show that indomethacin decreases the delivery of solute from the proximal tubule, reduces the fractional free water clearance, and increases the urine-plasma osmolar ratio. The rate of urinary excretion of prostaglandin E2 was high in all five children; it decreased below normal values in four of them after 1 week of treatment. In the child with nephrogenic diabetes insipidus who did not respond to indomethacin therapy, prostaglandin E2 excretion decreased but the rate remained higher than normal. These results suggest that indomethacin induces retention of solute and water mainly through an enhanced proximal tubular reabsorption.

Effect of acute unilateral renal denervation on tubular sodium reabsorption in the dog

1977 ◽  
Vol 232 (1) ◽  
pp. F16-F19
Author(s):  
G. Nomura ◽  
T. Takabatake ◽  
S. Arai ◽  
D. Uno ◽  
M. Shimao ◽  
...  
Keyword(s):  
Renal Denervation ◽  
Renal Plasma Flow ◽  
Free Water ◽  
Sodium Reabsorption ◽  
Distal Nephron ◽  
Water Diuresis ◽  
Free Water Clearance ◽  
Water Excretion ◽  
Tubular Sodium Reabsorption ◽  
Renal Tubular

The effects of acute denervation of the kidney on renal tubular sodium and water excretion were studied in anesthetized, hypophysectomized, and cortisone-treated mongrel dogs during stable water diuresis produced by the infusion of 2.5% dextrose. In all experiments, denervation natriuresis, and diuresis were observed without significant change in glomerular filtration rate (GRF) and renal plasma flow (RPF). Fractional sodium delivery to the distal nephron (CNa + CH2O/100 ml GFR) and fractional free water clearance (CH23/100 ml GFR) was significantly greater in the denervated kidney compared with the innervated kidney (9.6+/-1.2 vs. 6.7+/-0.9% and 8.8+/-1.2 vs. 6.5+/-0.8%, respectively). Distal tubular sodium reabsorption (CH2O/(CNa + CH2O)) was not significantly different. We conclude that renal denervation primarily affects the proximal tubule as manifested by a decrease in the reabsorption of sodium and water. A small effect of denervation on the distal nephron is not completely ruled out.

Morphological and functional comparisons of normal and hypertrophied kidneys of adult domestic fowl (Gallus gallus)

1990 ◽  
Vol 258 (2) ◽  
pp. F403-F413
Author(s):  
C. M. Gregg ◽  
R. F. Wideman
Keyword(s):  
Domestic Fowl ◽  
Renal Mass ◽  
Plasma Osmolality ◽  
Free Water ◽  
Urine Osmolality ◽  
Osmotic Diuresis ◽  
Free Water Clearance ◽  
Permanent Loss ◽  
The Right ◽  
Water Clearance

Similar to mammals, kidneys of domestic fowl undergo compensatory hypertrophy after loss of functional renal mass. Because this species continues to develop new nephrons for up to 12-wk posthatch, renal hyperplasia might play a significant role in compensatory growth. Either transient or permanent loss of approximately 60% of the right kidney was produced in 2- to 3-wk-old roosters by simple ureteral transection or by removing a 1-mm segment of ureter at the level of the ischiadic artery, respectively. In the latter (experimental) group, right anterior and medial divisions atrophied leaving only the posterior division intact. Spontaneous reanastomosis occurred in the former (reconnected) group, and all three divisions were present at death. Control birds were untouched as were the left kidneys of experimental and reconnected birds. At 40-50 wk, renal function was measured separately in right and left kidneys of all groups during five different infusion protocols. Compared with control kidneys, experimental kidneys had a 50-60% weight gain, and their glomerular size distribution profile was shifted to the right (larger glomeruli). Reconnected kidneys were not hypertrophied, and their profile was shifted to the left (smaller glomeruli). Neither group had significant formation of new nephrons. Once variations in kidney weight were taken into account, there were no differences between hypertrophied (experimental) and control kidneys in urine flow rate (UFR), glomerular filtration rate (GFR), paraaminohippuric acid (PAH) clearance, UFR/GFR, urine osmolality, urine/plasma osmolality, osmolal clearance, free water clearance, Na and K load, absolute Na and K excretion, and fractional Na and K excretion except as follows: 1) during infusion of isotonic mannitol-dextrose at 0.1 ml.min-1.kg body wt-1 experimental kidneys had a lower fractional excretion of K than control kidneys, and 2) during brisk osmotic diuresis (isotonic mannitol-dextrose at 0.4 ml.min-1.kg body wt-1) experimental kidneys had higher UFR and free water clearance and lower urine osmolality and urine/plasma osmolality than control kidneys. Reconnected kidneys differed from control kidneys in only 1 of 210 comparisons. Permanent loss of functional renal mass in young birds produces significant compensatory renal hypertrophy that is due to enlargement of existing nephrons rather than formation of new nephrons. Hypertrophied kidneys function like normal kidneys except under conditions of brisk osmotic diuresis.

Renal Clearance of Fluoride in Children and Adolescents

PEDIATRICS ◽  
1985 ◽  
Vol 75 (3) ◽  
pp. 575-579
Author(s):  
Carl-Johan Spak ◽  
Ulla Berg ◽  
Jan Ekstrand
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Free Water ◽  
Tubular Secretion ◽  
Urinary Flow ◽  
Water Diuresis ◽  
Free Water Clearance ◽  
Clearance Technique

Renal function and fluoride excretion have been studied in 38 children. The children were divided into three groups according to their glomerular filtration rate: normal (92 to 136 mL/min/1.73 m2 of body surface area [BSA]), low (< 92 mL/min/1.73 m2 BSA, and super-normal (> 136 mL/min/1.73 m2 BSA). Standard clearance technique with infusion of inulin and p-aminohippuric acid during water diuresis was used. Mean renal fluoride clearance was 45.0 ± 9.8 (SD) mL/min in the group of children with normal glomerular filtration rates and 31.4 ± 8.8 mL/min in the group with low glomerular filtration rates. This difference was statistically significant. There was a close linear relationship between renal fluoride clearance and glomerular filtration rate, urinary flow, and free water clearance. The fractional fluoride excretion did not differ between the groups. About 60% of the filtered fluoride was reabsorbed. No evidence for tubular secretion exceeding the reabsorption could be found. The results suggest that children have lower renal fluoride clearance rates than adults and indicate that a moderate impairment of the renal function could lead to increased retention of fluoride.

Effect of vasopressin on renal kallikrein excretion

1980 ◽  
Vol 239 (4) ◽  
pp. F388-F392 ◽  
Author(s):  
Géza Fejes-TÓth ◽  
Tibor Zahajszky ◽  
János Filep
Keyword(s):  
Technical Assistance ◽  
Free Water ◽  
Urinary Kallikrein ◽  
Water Diuresis ◽  
Free Water Clearance ◽  
Kinin System ◽  
Urinary Kallikrein Excretion ◽  
Renal Kallikrein ◽  
Kallikrein Kinin System ◽  
Induced Changes

In an attempt to investigate a possible interaction between vasopressin and the renal kallikrein-kinin system, renal function and urinary kallikrein excretion were monitored in trained conscious dogs and in anesthetized rats in water diuresis and in vasopressin-induced antidiuresis. Vasopressin elevated urinary kallikrein excretion in a dose-dependent way in both species, with concomitant increases in urinary osmolality and electrolyte excretion. A significant increase in kallikrein excretion was observed with a dose of vasopressin as low as 2 mU·kg-1·h-1 in the dog and 3 mU·kg-1·h-1 in the rat without a change in renal hemodynamics. In the rat vasopressin-induced changes in kallikrein excretion were positively correlated with changes in sodium and potassium excretion and negatively correlated with changes in free water clearance. It is concluded that vasopressin over its normal physiological range of concentration stimulates renal kallikrein secretion. Note: With the Technical Assistance of Klára Peres and Edit Spitzár water diuresis; antidiuresis; natriuresis; kinins; dog; rat Submitted on October 8, 1979 Accepted on May 21, 1980

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