Lithium clearance in dogs: effects of water loading, amiloride and lithium dosage

1992 ◽  
Vol 82 (6) ◽  
pp. 635-640 ◽  
Author(s):  
Michael SHALMI ◽  
Jørn Bech Laursen ◽  
Jacob Plange-RHULE ◽  
Sten Christensen ◽  
John Atherton ◽  
...  

1. The influences of lithium dosage, urine flow rate and acute administration of amiloride on the renal handling of lithium in normal conscious dogs were investigated. 2. Lithium was administered in the diet at daily doses of 100 mg or 2 mg of lithium carbonate for the 2 days preceding the investigation. Urine flow rate was altered by water loading with and without arginine vasopressin infusion (5 pg min−1 kg−1). Amiloride was administered as an intravenous bolus (130 μg/kg) followed by a continuous infusion (1.22 μg h−1 kg−1). 3. Glomerular filtration rate (exogenous creatinine clearance) did not change within series and was not different between series; it averaged 3.27 ml min−1 kg−1. Control levels of fractional lithium excretion (12.4 ± 1.2%, mean ± sem) were not influenced by hydration, hydration plus arginine vasopressin administration or the lithium dosage. However, in hydrated dogs having a plasma lithium concentration of 130–140 μmol/l, amiloride administration was associated with a 5% increase in fractional lithium excretion (P 0.01). 4. It is concluded that distal tubular lithium reabsorption may take place in sodium-replete conscious dogs undergoing water diuresis. The low fractional lithium excretion even during amiloride infusion (14.1–16.8%) may well be due to a high fractional reabsorption of lithium in the proximal tubules; however, a significant reabsorption of lithium distal to the proximal straight tubules by amiloride-insensitive pathways cannot be excluded.

1990 ◽  
Vol 79 (2) ◽  
pp. 117-121 ◽  
Author(s):  
Derek G. Waller ◽  
Satvinder S. Bhatia ◽  
Sara K. Campbell ◽  
Janet D. M. Albano ◽  
J. Gavin B. Millar

1. The urinary excretion of active and inactive kallikrein was studied in volunteers during diuresis induced by water loading or oral frusemide and during antidiuresis induced by desamino-d-arginine-vasopressin. 2. During acute oral water loading, excretion of active kallikrein was unchanged, despite high urine flow rates and low urine osmolalities being achieved. Excretion of inactive kallikrein correlated with the urine flow rate. 3. After desamino-d-arginine-vasopressin in eight water-loaded and six normally hydrated subjects, excretion of inactive kallikrein also correlated with the urine flow rate. There were no significant changes in the excretion of active kallikrein. 4. After frusemide there was a small transient increase in excretion of active kallikrein 1–2 h after dosing which coincided with the maximum diuresis and natriuresis. Excretion of inactive kallikrein again correlated with urine flow rate but the regression relationship between the two variables was different for water-load-induced and frusemide-induced diuresis. 5. These studies do not support a role for urinary kallikrein in the modulation of the antidiuretic action of vasopressin, but suggest that it may contribute to the natriuretic action of frusemide.


1989 ◽  
Vol 257 (4) ◽  
pp. F565-F573
Author(s):  
J. Ohanian ◽  
M. A. Young ◽  
Y. T. Shen ◽  
R. Gaivin ◽  
S. F. Vatner ◽  
...  

We studied the effects of 30-min infusions of the synthetic 25-amino acid atrial natriuretic factor [ANF-(102-126)] and the 28-amino acid ANF-(99-126) at 0.1 and 0.3 micrograms.kg-1.min-1 on urine flow rate, sodium excretion, and arterial pressure in conscious dogs. Each dose was administered on a separate day following a 1-h stabilization period. We also compared the effects of 60-min infusions of ANF, 0.01 micrograms.kg-1.min-1, or water infusion on separate days in conscious dogs. Arterial pressure was reduced in a dose-dependent fashion, reaching statistical significance at a dose of 0.3 micrograms.kg-1.min-1. During the 0.01-micrograms.kg-1.min-1 infusion, the plasma concentration of ANF rose approximately threefold (from 68 +/- 7 to 207 +/- 14 pg/ml), with no change in urine flow rate, sodium excretion, or arterial pressure. At a dose of 0.1 micrograms.kg-1.min-1, urine flow increased (P less than 0.05) by 0.41 +/- 0.15 ml/min, and sodium excretion rose by 72 +/- 24 mu eq/min, but not significantly, whereas plasma ANF levels rose to 1,236 +/- 229 pg/ml. At the highest dose of ANF (0.3 micrograms.kg-1.min-1) urine flow rose by 0.62 +/- 0.16 ml/min, P less than 0.05, and sodium excretion rose by 139 +/- 30 mu eq/min, P less than 0.05, whereas plasma levels of ANF rose to 2,436 +/- 320 pg/ml. In contrast, volume loading with dextran increased urine flow by 3.5 +/- 1.3 ml/min, P less than 0.05, and sodium excretion by 439 +/- 147 mu eq/min, P less than 0.05, whereas ANF rose to only 320 +/- 69 pg/ml. These results suggest that, in the conscious dog, ANF does not cause significant diuretic or natriuretic effects until plasma levels are markedly above those observed in physiological conditions. A possible explanation for the difference between this and previous studies is that the renal effects of ANF, at physiological plasma levels, are indirect and thus dependent on autonomic and hormonal (angiotensin, vasopressin, and aldosterone levels) factors governing the renal function of the animal.


1980 ◽  
Vol 238 (2) ◽  
pp. F107-F111 ◽  
Author(s):  
M. A. Kirschenbaum ◽  
E. R. Serros

The relationships between urinary prostaglandin E excretion and urine flow rate were evaluated in 11 conscious mongrel dogs during antidiuresis, maximal water loading, vasopressin administration during maximal water loading, and mannitol infusion. Urine flow rates between 0.21 and 15.1 ml/min were achieved. Urinary prostaglandin E excretion rates, determined by a membrane receptor assay, varied directly with urine flow rates (r = 0.908). Vasopressin administration (34--540 microU . kg-1 . min-1) resulted in a fall, rather than the expected rise, in urinary prostaglandin E excretion. When the concentration of prostaglandin E in the urine was plotted against urine flow rate, the demonstrated relationship appeared most consistent with passive diffusion. Mannitol infusion increased urine flow rates to levels comparable to the levels seen with maximal water loading but did not result in a fall in plasma osmolality. Urinary prostaglandin E excretion rates, however, were not distinguishable from those in the previous group. These data demonstrate that urinary prostaglandin E excretion rates are determined, to a great extent, by urine flow rate and that the significance of the interpretation of elevated excretion levels of these lipids in diuretic states may have to be reevaluated.


Author(s):  
Mark T Houser

To substantiate the effects of urine flow rate on renal lysozyme handling and N-acetyl-β-d-glucosaminidase (NAG) excretion, experiments were performed in normal human subjects. Urine flow rate was varied by overnight fluid deprivation and progressive diuresis induced by oral water loading. Lysozyme measurements were made using an improved turbidimetric method and NAG determinations using a modified fluorometric assay utilising individual recovery techniques. Fractional lysozyme clearance and lysozyme excretion demonstrated a nearly linear relationship with urine flow rate ( r=0·78, r=0·80, P<0·0005), and both were elevated significantly in samples obtained during diuresis. NAG excretion, however, demonstrated a significant but weak correlation ( r=0·47, P<0·005) with fractional urine flow rate. A significant ( P<0·05) difference in NAG activity occurred only during the period of hydropenia, when a decrease in excretion was observed. These findings suggest that the effect of diuresis on lysozyme excretion should be considered in studies utilising this enyzyme as a marker of renal injury.


1972 ◽  
Vol 15 (4) ◽  
pp. 338-346 ◽  
Author(s):  
Herbert S. Diamond ◽  
Robert Lazarus ◽  
David Kaplan ◽  
David Halberstam

1988 ◽  
Vol 254 (2) ◽  
pp. R357-R380 ◽  
Author(s):  
L. Rabinowitz ◽  
D. M. Green ◽  
R. L. Sarason ◽  
H. Yamauchi

In unanesthetized adult sheep, following intake of a daily meal, there was a peak in K excretion. The maximum and minimum rates of K excretion following meals were directly related to meal K content. On days without meals, no peak in K excretion occurred. Changes in K excretion on fed and fast days occurred without changes in the low levels of plasma aldosterone and were poorly correlated with urine or blood pH, urine flow rate, Na excretion, or the filtered load of K, but they correlated well with fractional K excretion. Plasma K did not change on fast days. Plasma K increased on some, but not all, fed days. Increases in plasma K that occurred on fed days were insufficient to account for the concurrent kaliuresis. Infusion of aldosterone or isotonic NaCl failed to alter K excretion in fed or fasted sheep. Infusion of isotonic NaCl + aldosterone hypertonic Na2SO4 + aldosterone increased K excretion in fasted but not fed sheep. Infusion of K in the rumen of fed and fasted sheep elevated rumen K concentration and led to increases in K excretion that could not be explained by increases in plasma K. The mechanisms responsible for the homeostatic changes in K excretion on fed and fast days were not ascertained but may importantly depend on sensors of enteric K content.


Author(s):  
Katja M. Gist ◽  
Jamie Penk ◽  
Eric L. Wald ◽  
Laura Kitzmiller ◽  
Tennille N. Webb ◽  
...  

AbstractA standardized, quantified assessment of furosemide responsiveness predicts acute kidney injury (AKI) in children after cardiac surgery and AKI progression in critically ill adults. The purpose of this study was to determine if response to furosemide is predictive of severe AKI in critically ill children outside of cardiac surgery. We performed a multicenter retrospective study of critically ill children. Quantification of furosemide response was based on urine flow rate (normalized for weight) measurement 0 to 6 hours after the dose. The primary outcome was presence of creatinine defined severe AKI (Kidney Disease Improving Global Outcomes stage 2 or greater) within 7 days of furosemide administration. Secondary outcomes included mortality, duration of mechanical ventilation and length of stay. A total of 110 patients were analyzed. Severe AKI occurred in 20% (n = 22). Both 2- and 6-hour urine flow rate were significantly lower in those with severe AKI compared with no AKI (p = 0.002 and p < 0.001). Cutoffs for 2- and 6-hour urine flow rate for prediction of severe AKI were <4 and <3 mL/kg/hour, respectively. The adjusted odds of developing severe AKI for 2-hour urine flow rate of <4 mL/kg/hour was 4.3 (95% confidence interval [CI]: 1.33–14.15; p = 0.02). The adjusted odds of developing severe AKI for 6-hour urine flow rate of <3 mL/kg/hour was 6.19 (95% CI: 1.85–20.70; p = 0.003). Urine flow rate in response to furosemide is predictive of severe AKI in critically ill children. A prospective assessment of urine flow rate in response to furosemide for predicting subsequent severe AKI is warranted.


1983 ◽  
Vol 105 (1) ◽  
pp. 351-362 ◽  
Author(s):  
A. J. MCVICAR ◽  
J. C. RANKIN

1. Improved estimates of urine flow rates of lampreys in various salinities were obtained by the collection of urine for periods of up to 48 h from minimally-stressed, unanaesthetized fish, following catheterization of the urinogenital papilla. 2. The mean urine flow rate of freshwater lampreys was 200.7 ±14.3 ml kg−1 day−1. 3. Urine flow in freshwater lampreys was correlated with spontaneous changes in gill ventilation rate. MS222 anaesthesia reduced both ventilation and urine flow rates, but pronounced effects were only observed at concentrations greater than those needed to induce light anaesthesia (50–55 mg 1−1). Urine flow rate in unanaesthetized fish was extremely sensitive to rapid (6°Ch−1) changes in temperature and Q10 (6–16°C) was approximately 5. 4. Urine flow rate decreased rapidly as the osmotic difference between the body fluids and environment approached zero, and the rate of flow in 30% seawater lampreys was only 7.6% that of freshwater fish. 5. There was no evidence for an effect of environmental calcium concentration on branchial osmotic permeability. 6. Extensive tubular reabsorption of ions occurred in freshwater lampreys. The total daily excretion rate of sodium ions generally decreased in salinities hyperosmotic to the plasma, indicating enhanced reabsorption, but secretion of magnesium and sulphate ions was greatly increased. Urine osmolarity was significantly increased in lampreys in hyperosmotic salinities. 7. Present data compare favourably with data obtained previously from anaesthetized animals, indicating that renal function in lampreys is not significantly impaired by light MS222 anaesthesia.


1995 ◽  
Vol 7 (5) ◽  
pp. 1311 ◽  
Author(s):  
EM Wintour ◽  
R Riquelme ◽  
C Gaete ◽  
C Rabasa ◽  
E Sanhueza ◽  
...  

Samples of maternal and fetal plasma, fetal urine, and amniotic fluid were collected from 8 chronically cannulated pregnant llamas, in the last third of gestation. The samples were obtained for up to 18 days post-surgery. Osmolality, sodium (Na), potassium (K), chloride (Cl), and urea were measured on 40 samples collected on days 1, 2, 3, 4-5, 6-7, 8-9, and 10-19. The osmolalities of maternal and fetal plasma, fetal urine and amniotic fluid, averaged over these 7 time periods, were, respectively, 312 +/- 2, 311 +/- 1, 484 +/- 14, and 317 +/- 1 mosmol kg-1. Values are given as mean +/- s.e. The major differences from fetal fluid values in the ovine fetus (from previously published values) were the higher osmolality and urea concentration of llama fetal urine. Urine flow rate measured in 6 fetuses, 4.5-6.5 kg body weight, was 5.8 +/- 0.4 mliter h-1; urea clearance rate was 55.5 +/- 11.8 mliter h-1. Glomerular filtration rate (GFR), measured with 51Cr-EDTA in 5 fetuses on 1-4 occasions, was 111.4 +/- 23.3 mliter h-1. Fractional reabsorptions (FR) of Na, K and Cl were 97.9 +/- 1, 75.9 +/- 13.5 and 97.7 +/- 0.4% respectively. The GFR (25 mliter kg-1 h-1) and urine flow rate (1 mL kg-1 h-1) were less than half and about one-tenth the respective values in ovine fetuses. As Na reabsorption is the major oxygen-consuming activity of the kidney, the llama fetal kidney requires only half the oxygen needed by the ovine fetal kidney to reabsorb the filtered sodium load. The reason for the formation of hypertonic, rather than hypotonic, urine in the fetal llama may be due to both greater morphological maturity of the kidney and the excretion of as yet unidentified osmotically active organic substances.


1986 ◽  
Vol 251 (3) ◽  
pp. R639-R642 ◽  
Author(s):  
D. W. Duff ◽  
K. R. Olson

Dorsal aortic pressure (DAP), urine flow rate, and urinary K+, Na+, and Cl- were monitored in chronically catheterized unanesthetized rainbow trout before and after injection of saline, tissue extracts, or synthetic (rat, Ile-26) atrial natriuretic factor (ANF). Synthetic ANF (1.0 and 10.0 micrograms/kg body wt) and extracts from trout atria and ventricles increased DAP, urine flow rate, and electrolyte excretion. Saline, skeletal muscle extracts, and 0.1 microgram/kg body wt synthetic ANF had no effect on DAP and only minor effects on renal water and ion excretion. The slow-onset long-duration pressor response to ANF and heart extracts contrasted with a rapid short-acting pressor effect of epinephrine. Synthetic ANF (10 micrograms/kg body wt) and ventricular extracts produced marked increases in Na+ and Cl- excretion but only a mild diuresis. Much of the increase in urine flow rate appears to be due to solvent injection. These results show that trout hearts contain an ANF-like material and that mammalian and piscine ANF produce hemodynamic and renal effects upon intra-arterial injection.


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