On the interaction of calcium, sodium, and water transport in the diuresing kidney

1968 ◽  
Vol 46 (2) ◽  
pp. 275-280 ◽  
Author(s):  
O. Schück ◽  
J. H. Cort
Keyword(s):  
Renal Function ◽  
Linear Relation ◽  
Filtration Rate ◽  
Urine Flow ◽  
Water Reabsorption ◽  
Osmotic Diuresis ◽  
Anesthetized Dogs ◽  
Permeability For Water ◽  
Solute Excretion ◽  
Tubular Permeability

Diuresis was induced in cats by infusion of 3% glucose in 10% ethanol. When urine flow had stabilized at high levels a solution of the Ca salt of ethylenediaminetetraacetate (Na2CaEDTA) was infused as a control for the effect of the EDTA molecule on renal function. The infusion was then changed over to the same molar rate of Na2EDTA, which resulted in a 30% decrease in serum Ca levels. Ca was then repleted rapidly as CaCl2 given intravenously, and the infusion was shifted back to Na2CaEDTA. The decrease in extracellular Ca concentration was associated with a significant antidiuresis. In further experiments on anesthetized dogs, osmotic diuresis was induced either by (a) infusion of hyperosmotic mannitol solutions, which were then shifted over to hypertonic NaCl, or (b) the same solutions in reverse order. Ca excretion correlated in linear fashion with Na excretion, but not with total solute excretion or with filtration rate. When Ca was added to the mannitol infusion, Na excretion increased in linear relation to Ca. It is suggested that Ca (a) decreases tubular permeability for water reabsorption and (b) decreases Na reabsorption, while Na (c) decreases Ca reabsorption. Mechanisms a and b would appear to involve membrane transport directly in the proximal tubule.

scholarly journals Osmoregulation by Nestling and Adult American Kestrels (Falco Sparverius)

The Auk ◽  
2002 ◽  
Vol 119 (2) ◽  
pp. 426-436
Author(s):  
Michele E. Lyons ◽  
David L. Goldstein
Keyword(s):  
Renal Function ◽  
Filtration Rate ◽  
Tubular Secretion ◽  
Urine Flow ◽  
High Protein ◽  
Falco Sparverius ◽  
Water Reabsorption ◽  
Protein Food ◽  
Ion Concentrations ◽  
American Kestrels

Abstract We explored aspects of renal function in American Kestrels (Falco sparverius), birds that habitually eat high-protein meals. In particular, we hypothesized that, like granivorous birds switched to high-protein food, kestrels would have high urine flows with high proportions of waste N as urate. In nestlings in the field, 80–93% of urinary N was in the form of urate, though concentrations of ammonia and urea were higher in older nestlings. Feeding resulted in reduced osmotic and ion concentrations in urine, but concentrations and proportions of nitrogenous wastes were unaffected. In adult kestrels in the laboratory, urine flow rate in fed animals, ∼1 mL h–1, was similar to that previously measured in avian granivores. Urine flow declined with fasting, accomplished by both a reduction in glomerular filtration rate (significant after 24 h fast) and a rise in tubular water reabsorption (significant after 48 h). During the course of a 48 h fast, proportion of urinary N excreted as urate fell and that as ammonia rose. Both filtration and secretion of urate dropped during fasting, so that tubular secretion remained responsible for ∼90% of urinary urate. Composition of fluid voided from the cloaca differed little from that of the ureteral urine.

Influence of hydration on renal function and medullary sodium during vasopressin infusion

1962 ◽  
Vol 202 (6) ◽  
pp. 1098-1104 ◽  
Author(s):  
Joseph H. Perlmutt
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Filtration Rate ◽  
Urine Flow ◽  
Constant Infusion ◽  
Water Diuresis ◽  
Vasopressin Infusion ◽  
Degree Of Hydration ◽  
Anesthetized Dogs ◽  
Influence Of Hydration

Mild and severe degrees of hydration were produced in anesthetized dogs by constant infusion of dextrose in water at different rates. When water diuresis ensued, and after adequate control periods, vasopressin was infused for 2 1/2 hr. The magnitudes of urine flow and Na excretion varied directly and osmolal urine-to-plasma ratio varied inversely with the degree of hydration. During mild hydration, glomerular filtration rate and osmolal clearance remained practically unchanged, whereas during severe hydration they increased. In another group of animals, similarly prepared, kidneys were removed at appropriate times and tissue was obtained from various areas for Na analysis. During uninterrupted water diuresis the medullary gradient for Na was practically dissipated. Vasopressin promoted the repletion of medullary Na during mild hydration, but only slightly ameliorated the disturbance during severe hydration. These data demonstrate that during vasopressin infusion the renal concentrating response and Na excretion were significantly modified by the degree of hydration, and evidence is presented for several possible causes.

Renal function and plasma levels of arginine vasotocin during free flight in pigeons.

1997 ◽  
Vol 200 (24) ◽  
pp. 3203-3211 ◽  
Author(s):  
I Giladi ◽  
D L Goldstein ◽  
B Pinshow ◽  
R Gerstberger
Keyword(s):  
Glomerular Filtration ◽  
Plasma Levels ◽  
Filtration Rate ◽  
Control Level ◽  
Urine Osmolality ◽  
Urine Flow ◽  
Arginine Vasotocin ◽  
Free Flight ◽  
Water Reabsorption ◽  
Before And After

We examined urinary water loss and plasma levels of arginine vasotocin (AVT) in free-flying, tippler pigeons trained to fly continuously for up to 5 h. First, we used [3H]polyethyleneglycol ([3H]PEG) as a glomerular filtration marker by implanting an osmotic minipump into each bird. In two flights (10 birds in winter at an ambient temperature of 13-15 degrees C and seven in summer at 23 degrees C), we measured pre-flight (hydrated, resting control birds) and post-flight [3H]PEG activity and osmolality in blood and ureteral urine. For comparison, we measured these variables in 10 birds in winter before and after controlled dehydration (24 h at 25 or 30 degrees C). Second, we measured plasma levels of AVT in 6-8 birds before and immediately after each of three different summer flights. Urine osmolality increased significantly by up to three times the control level in both post-flight and dehydrated pigeons; urine:plasma osmolality ratios did not exceed 2. Compared with controls, glomerular filtration rate (GFR) was significantly lower after flight in summer, but did not change in either post-flight or dehydrated winter pigeons. In winter, mean post-flight urine flow rate (UFR) decreased significantly to less than half the control level, while in summer, post-flight UFR did not differ from control levels. In general, mean filtered water reabsorption (FrH2O) increased from 95 % in controls to 98 % in post-flight and dehydrated birds. Plasma levels of AVT increased after flight to between three and eight times the preflight levels. The data from this first study of kidney function during flight are consistent with previous studies of dehydration in birds and exercise in mammals in which both increased FrH2O and decreased GFR contribute to renal conservation of water.

Effects of atriopeptin infusion versus effects of left atrial stretch in awake dogs

1986 ◽  
Vol 250 (2) ◽  
pp. R221-R226 ◽  
Author(s):  
K. L. Goetz ◽  
B. C. Wang ◽  
P. G. Geer ◽  
W. D. Sundet ◽  
P. Needleman
Keyword(s):  
Renal Function ◽  
Left Atrial ◽  
Free Water ◽  
Urine Flow ◽  
The Other ◽  
Potassium Excretion ◽  
Water Reabsorption ◽  
Hemodynamic Responses ◽  
Systemic Hemodynamic ◽  
Left Atrial Distension

We infused synthetic atriopeptin III intravenously into 10 conscious dogs while monitoring renal function and systemic hemodynamics. The results obtained from these infusion experiments were compared with results from other experiments in which left atrial distension was performed in the same dogs. Both atriopeptin infusion and left atrial distension caused significant increases in urine flow, sodium excretion, potassium excretion, and free water reabsorption and a significant decrease in renal blood flow. On the other hand, the pattern of systemic hemodynamic responses to atriopeptin infusion were quite different from the hemodynamic responses elicited by left atrial distension. However, there was a striking concordance between the renal effects of atriopeptin and those of left atrial distension. We therefore hypothesize that the renal response to left atrial distension in the conscious dog is mediated largely by the release of natriuretic peptides from the atria.

Renal actions of endothelin: interaction with prostacyclin

1990 ◽  
Vol 259 (4) ◽  
pp. F645-F652 ◽  
Author(s):  
S. Y. Chou ◽  
A. Dahhan ◽  
J. G. Porush
Keyword(s):  
Blood Pressure ◽  
Filtration Rate ◽  
Prostaglandin Synthesis ◽  
Urine Flow ◽  
Renin Release ◽  
Arterial Blood ◽  
Anesthetized Dogs ◽  
Inhibition Of Prostaglandin Synthesis ◽  
Arterial Plasma ◽  
Prostacyclin Synthesis

The renal actions of endothelin were examined by infusing it intrarenally in anesthetized dogs at 4 ng.min-1.kg-1 without affecting arterial blood pressure or cardiac output. Endothelin infusion caused a transient and significant increase in renal blood flow (RBF) by 13 +/- 2%, followed by large decreases in RBF and glomerular filtration rate (GFR; by 26 +/- 2 and 23 +/- 7%, respectively) but did not alter urine flow rate or absolute sodium excretion. After endothelin infusion, renal venous and arterial plasma 6-ketoprostaglandin F1 alpha increased from 250 +/- 58 and 117 +/- 31 to 1,044 +/- 249 and 617 +/- 211 pg/ml, respectively, and its renal output increased from 339 +/- 99 to 963 +/- 202 pg.min-1.g-1 (P less than 0.01 for all). The renal prostacyclin synthesis was augmented by endothelin without stimulating the renal renin release or norepinephrine output. Inhibition of prostaglandin synthesis with indomethacin partially prevented the early renal vasodilation induced by endothelin, which then caused a more pronounced decline in RBF and GFR (by 65 +/- 7 and 54 +/- 8%, respectively). With suppression of prostacyclin synthesis, inhibition of renin release by endothelin was observed. Thus the vasoconstrictive effects of endothelin on renal hemodynamics are significantly modified by its ability to enhance production of vasodilators, including prostacyclin.

Effect of sodium lactate on urate clearance in the Dalmatian and in the mongrel

1964 ◽  
Vol 207 (1) ◽  
pp. 113-117 ◽  
Author(s):  
Gabrielle H. Reem ◽  
Parker Vanamee
Keyword(s):  
Filtration Rate ◽  
Inhibitory Effect ◽  
Sodium Lactate ◽  
Tubular Secretion ◽  
Urine Flow ◽  
Osmotic Diuresis ◽  
Significant Drop ◽  
Urate Reabsorption

Sodium lactate was infused and urate clearance was measured under conditions of osmotic diuresis alone, as well as during simultaneous urate infusion. Urate clearance in the Dalmatian was not depressed by the administration of sodium lactate of 1.2–9.3 mEq/kg dl-sodium lactate, indicating that sodium lactate has no inhibitory effect on tubular secretion of urate. dl-Sodium lactate, 0.54–11.8 mEq/kg, was administered to four mongrel dogs in five experiments. In three experiments a significant drop of urate clearance in relation to filtration rate was observed. In two experiments in which urine flows exceeded 10 ml/min no significant decrease in urate clearance was recorded following dl-sodium lactate administration. The depression of urate clearance in the mongrel under conditions of moderate urine flow where reabsorption of solutes is more easily accomplished, and the absence of this effect in the Dalmatian as well as in the mongrel under conditions of vigorous diuresis where reabsorption of solutes is greatly diminished, lends support to the belief that sodium lactate depresses urate clearance by facilitating urate reabsorption in the mongrel.

Mechanism of renal excretion of methylurea and acetamide in the dog

1965 ◽  
Vol 209 (1) ◽  
pp. 188-194 ◽  
Author(s):  
Lawrence Rabinowitz
Keyword(s):  
Renal Excretion ◽  
Inulin Clearance ◽  
Passive Transport ◽  
Water Reabsorption ◽  
Osmotic Diuresis ◽  
Active Secretion ◽  
Anesthetized Dogs ◽  
Filtered Load

The renal excretion of methylurea, acetamide, and urea was studied in anesthetized dogs during a graded osmotic diuresis produced by infusion of mannitol, urea, methylurea, or acetamide. Within the urine-to-plasma inulin range of 3–300, the clearances of these compounds relative to the inulin clearance were less than 1.0 while their urine-to-plasma ratios were greater than 1.0. For all compounds the urine-to-plasma ratios and the amount reabsorbed were directly related to water reabsorption. No dependence of reabsorption on filtered load and no transport maxima at high filtered loads were observed. These results suggest reabsorption of all three compounds by passive transport and indicate the absence of a quantitatively appreciable active secretion or reabsorption.

Abnormal tubular permeability in hypothermic perfused kidneys

1975 ◽  
Vol 38 (4) ◽  
pp. 615-622
Author(s):  
A. Small ◽  
R. T. Bell ◽  
R. S. Filo
Keyword(s):  
Perfusion Pressure ◽  
Urine Flow ◽  
Isotonic Fluid ◽  
Tubular Lumen ◽  
Anesthetized Dogs ◽  
Pah Clearance ◽  
Pressure Phase ◽  
Tubular Permeability ◽  
Ureteral Occlusion

Isolated canine kidneys perfused with cryoprecipitated plasma at 15 degrees C exhibit unexpectedly low inulin clearance (CIn) and creatinine clearance (CCr) rates. CIn and CCr, as well as p-aminohoppurate (PAH) clearance, varied linearly with urine flow rate, whether the variations in urine flow were spontaneous or induced, either by elevating perfusion pressure or by adding mannitol to the perfusate. Retrograde intraureteral injection (RII) of an isotonic fluid containing dextran, inulin, and PAH, followed by a period of ureteral occlusion and subsequent serial recollection of the injected fluid, revealed that inulin and PAH, relative to dextran, were lost from distal tubular fluid. Similar experiments in anesthetized dogs indicated no loss of inulin or PAH from tubules of in situ kidneys. Renal venous perfusate, collected from isolated kidneys during the low pressure phase of the RII, contained the following percentages of the quantities injected intraluminally: dextran, 9.22%; inulin, 11.0%; and PAH, 22.0%. These data indicate that a low measured glomerular filtration rate in hypothermic perfused kidneys is partly due to diffusion of inulin or creatinine out of the tubular lumen.

Effect of vasopressin on sodium excretion and plasma antinatriferic activity in the dog

1976 ◽  
Vol 231 (1) ◽  
pp. 28-33 ◽  
Author(s):  
VM Buckalew ◽  
KA Dimond
Keyword(s):  
Glomerular Filtration Rate ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Urine Flow ◽  
Potassium Excretion ◽  
State Control ◽  
Sham Control ◽  
Anesthetized Dogs ◽  
Renal Tubular ◽  
Steady State Control

Vasopressin (VP) was administered for 1 h intravenously to hydropenic, anesthetized dogs in doses of 1.0-1.25 mU/kg per min. In 14 experiments, sodium excretion (UNA V) increased from a mean of 13 +/- 5 to a peak of 96 +/- 21 mueq/min 40 min after beginning infusion (P less than .001). Urine flow and potassium excretion increased from 0.18 +/-.04 ml/min and 20 +/- 2 meuq/min to peak values of 0.6 +/- .08 ml/min and 61 +/- 9 mueq/min, respectively (P less than .001), with no significant increase in glomerular filtration rate. No significant changes in UNA V occurred in eight sham control experiments of in six experiments in which VP was given at 75 muU/kf per min. To test the hypothesis that VP might be natriuretic indirectly by releasing a natriuretic substance, plasms ultrafiltrates were tested for toad bladder antinatriferic activity(AA). During steady-state control, AA was -10 +/- 3%. Thirty and sixty minutes after beginning VP, AA increased to -24 +/- 3% (P less than .05) and -26 +/- 2% (P less than .001), respectiviely. No significant change in plasma AA occurred in either sham controls or in animals given the subnatriuretic VP dose. Incubation of plasma with 1,000 muU/ml VP caused no increase in AA. The data show that VP natriuresis is accompanied by an increase in plasms AA. The results suggest that vasopressin natriuresis in hydropenic dogs at least in part to the release of a humoral inhibitor of renal tubular sodium transport.

Unilateral renal ischaemia in the rat: Effect of contralateral nephrectomy and intrarenal flush with phosphate-buffered sucrose

1988 ◽  
Vol 74 (3) ◽  
pp. 261-268 ◽  
Author(s):  
O. S. Ferwana ◽  
S. C. Pirie ◽  
D. J. Potts
Keyword(s):  
Renal Failure ◽  
Renal Function ◽  
Acute Renal Failure ◽  
Kidney Tissue ◽  
Urine Flow ◽  
Compensatory Response ◽  
Contralateral Kidney ◽  
Renal Ischaemia ◽  
Ischaemic Damage ◽  
Solute Excretion

1. This study examined whether the severity of acute renal failure seen within 4 h of a 45 min period of unilateral occlusion of the renal pedicle could be reduced by removal of the contralateral healthy kidney and/or intrarenal flush with a phosphate-buffered sucrose (PBS50) solution. 2. After ischaemia, unflushed kidneys became oliguric and isosthenuric, with a fall in inulin clearance (Cin) to 0.1% of the pre-ischaemic value. Removal of the healthy contralateral kidney upon release of the occlusion caused no improvement in immediate post-ischaemic function. 3. Intrarenal flush with 1.5 ml of PBS50 resulted in a significantly improved post-ischaemic Cin, with increased urine flow rate and solute excretion; urine was also concentrated. 4. Protection of renal function against ischaemic damage was seen only when kidney tissue remained blood-free and exposed to PBS50 throughout the period of ischaemia, and when the speed of flush was similar to the expected renal blood flow (6 ml/min). Protection did not depend upon the presence or absence of the contralateral kidney. 5. The study also showed that functional removal of one kidney, either by pedicle occlusion or nephrectomy, caused an immediate rise in solution excretion from the contralateral kidney, but Cin remained unchanged. Unflushed severely damaged kidneys showed no compensatory response to unilateral nephrectomy, whereas kidneys flushed with PBS50 exhibited increases in solute excretion similar to those seen in healthy non-ischaemic kidneys.

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