RENAL DIURESIS AFTER INJECTIONS OF THE FRESHWATER EEL AND ANTIDIURESIS ARGININE VASOTOCIN IN (ANGUILLA ANGUILLA L.)

1974 ◽  
Vol 61 (3) ◽  
pp. 487-500 ◽  
Author(s):  
I. W. HENDERSON ◽  
N. A. M. WALES
Keyword(s):  
Body Weight ◽  
Glomerular Filtration ◽  
Free Water ◽  
Anguilla Anguilla ◽  
Arginine Vasotocin ◽  
Free Water Clearance ◽  
Response Characteristics ◽  
Arterial Blood ◽  
Urine Production ◽  
Water Clearance

SUMMARY The renal responses of the freshwater-adapted eel, Anguilla anguilla L. to arginine vasotocin ([8-arginine]-oxytocin) have been examined. The quality of the responses to the intravenously administered peptide was found to vary with the dose. Less than 0·1 ng/kg body weight reduced glomerular filtration rate, free water clearance and rate of urine production for up to 60 min. Doses greater than 1·0 ng/kg body weight induced a 'glomerular diuresis', i.e. increased rates of urine production, glomerular filtration and free water clearance for 40–60 min. Neither the diuretic nor the antidiuretic doses produce changes in urinary composition, and no obvious direct tubular actions of the peptide were found. Arterial blood pressure, measured in the dorsal aorta, increased with some of the diuretic doses, whilst the lower doses (less than 10 ng/kg body weight) had little or no cardiovascular actions. The mechanisms involved in these dose—response characteristics are discussed with particular regard to the renal function of lower vertebrates. It is suggested that arginine vasotocin plays a primary or secondary role in the modulation of 'glomerular intermittency'.

scholarly journals Age and renal prostaglandin inhibition during exercise and heat stress

1999 ◽  
Vol 86 (6) ◽  
pp. 1936-1943 ◽  
Author(s):  
W. B. Farquhar ◽  
W. L. Kenney
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Filtration Rate ◽  
Acute Exercise ◽  
Free Water ◽  
Placebo Control ◽  
Free Water Clearance ◽  
Urine Production

Aging is associated with a number of physiological changes that may cause the kidney to rely to a greater extent on vasodilatory PGs for normal functioning. Acute exercise has been shown to cause renal vasoconstriction that may be partially buffered by vasodilatory PGs. To determine the relative importance of renal PGs during exercise in older adults, we compared the renal effects of the PG inhibitor ibuprofen (1.2 g/day for 3 days) vs. a placebo control in a cohort of eight younger (24 ± 2 yr) and eight older (64 ± 2 yr) women during treadmill exercise (∼57% maximal oxygen consumption) in the heat (36°C). This over-the-counter dose of ibuprofen reduced renal PG (i.e., PGE2) excretion by 47% ( P < 0.05). Acute exercise in the heat caused dramatic decreases in glomerular filtration rate, renal blood flow, and sodium excretion in both age groups. PG inhibition was associated with greater decreases in urine production and free water clearance ( P < 0.05). There were no drug-related declines in glomerular filtration rate or renal blood flow. We conclude that PG inhibition has only modest effects on renal function during exercise. Also, the lack of hemodynamic changes with PG inhibition indicates that healthy well-hydrated older women are not in a renal PG-dependent state.

Aldosterone increases urine production and decreases apical AQP2 expression in rats with diabetes insipidus

2006 ◽  
Vol 290 (2) ◽  
pp. F438-F449 ◽  
Author(s):  
Jakob Nielsen ◽  
Tae-Hwan Kwon ◽  
Jeppe Praetorius ◽  
Jørgen Frøkiær ◽  
Mark A. Knepper ◽  
...  
Keyword(s):  
Creatinine Clearance ◽  
Diabetes Insipidus ◽  
Free Water ◽  
Sodium Balance ◽  
Apical Plasma Membrane ◽  
Sodium Reabsorption ◽  
Outer Medulla ◽  
Free Water Clearance ◽  
Urine Production ◽  
Water Clearance

Vasopressin and aldosterone are essential hormones in the regulation of water and sodium balance. Aldosterone regulates sodium reabsorption, although synergistic effects on collecting duct water permeability have been shown. We investigated the effects of 7-day aldosterone infusion or oral spironolactone treatment on water balance and aquaporin (AQP) 2 expression in rats with 21 days of lithium-induced nephrogenic diabetes insipidus (Li-NDI). In rats with Li-NDI, aldosterone markedly increased (271 ± 14 ml/24 h), whereas spironolactone decreased (74 ± 11 ml/24 h) urine production compared with rats treated with lithium only (120 ± 11 ml/24 h). Aldosterone increased free-water clearance and creatinine clearance, whereas spironolactone caused a decreased creatinine clearance but unchanged free-water clearance. Immunoblotting showed unchanged AQP2 expression in cortex/outer stripe of the outer medulla and inner medulla. In the inner stripe of the outer medulla aldosterone caused a decreased AQP2 expression, whereas spironolactone caused an increase compared with rats treated with lithium only. Semiquantitative confocal immunofluorescence microscopy of AQP2 immunolabeling showed reduced AQP2 expression in the apical plasma membrane domain in connecting tubule (CNT) and initial cortical collecting ducts (iCCD) in response to aldosterone-treated rats compared with rats treated with lithium only. Spironolactone significantly increased apical AQP2 expression in the iCCD compared with rats treated with lithium only. We also tested whether similar changes could be observed in vasopressin-deficient BB rats and found similar changes in urine production and subcellular AQP2 expression in the CNT and iCCD in response to aldosterone and spironolactone. This study shows that aldosterone treatment perturbs diabetes insipidus and is associated with AQP2 redistribution in CNT and iCCD likely mediated by the spironolactone-sensitive mineralocorticoid receptor.

Body fluid balance in dehydrated healthy older men: thirst and renal osmoregulation

1994 ◽  
Vol 76 (4) ◽  
pp. 1615-1623 ◽  
Author(s):  
G. W. Mack ◽  
C. A. Weseman ◽  
G. W. Langhans ◽  
H. Scherzer ◽  
C. M. Gillen ◽  
...  
Keyword(s):  
Body Fluid ◽  
Fluid Intake ◽  
Plasma Osmolality ◽  
Free Water ◽  
Older Individuals ◽  
Total Fluid Intake ◽  
Free Water Clearance ◽  
Stimulus Response ◽  
Response Characteristics ◽  
Water Clearance

We examined osmotic control of thirst and free water clearance in healthy older (65+, n = 10) and younger (Y, n = 6) subjects during a 3-h rehydration period after an approximately 2.4% decrease in body weight. Plasma volume (PV), plasma osmolality (Posm), renal function, and thirst were measured before and after dehydration and during rehydration. In 65+, baseline PV was lower (43.1 +/- 1.6 vs. 48.1 +/- 2.5 ml/kg), Posm was higher (287 +/- 1 vs. 281 +/- 2 mosmol/kgH2O), and perceived thirst was lower than in Y. During dehydration, the osmotic threshold for increased thirst was shifted to a higher Posm in 65+. Total fluid intake was greater in Y than in 65+ (16.6 +/- 4.1 vs. 8.9 +/- 2.0 ml/kg); however, the relation between thirst and the rate of fluid intake was identical. Thus the blunted rehydration in 65+ is related to a lower overall sensation of thirst. The stimulus-response characteristics of osmotic control of free water clearance was similar in 65+ and Y; however, 65+ operated around a higher Posm and on a less-steep portion of the stimulus-response curve. These data support the hypothesis that the hyperosmotic hypovolemic state of healthy older individuals is not a result of a simple water deficit but represents a shift in the operating point for control of body fluid volume and composition.

Renal and humoral responses to sustained cardiopulmonary baroreceptor deactivation in humans

1991 ◽  
Vol 260 (3) ◽  
pp. R642-R648 ◽  
Author(s):  
J. A. Miller ◽  
J. S. Floras ◽  
K. L. Skorecki ◽  
L. M. Blendis ◽  
A. G. Logan
Keyword(s):  
Lower Body Negative Pressure ◽  
Renal Plasma Flow ◽  
Venous Pressure ◽  
Plasma Concentrations ◽  
Free Water ◽  
Plasma Norepinephrine ◽  
Free Water Clearance ◽  
Arterial Blood ◽  
Cardiopulmonary Baroreflex ◽  
Water Clearance

The renal and neurohumoral effects of prolonged cardiopulmonary baroreflex unloading and the relationship of these changes to urinary sodium excretion have not been well documented in humans. In this study, 12 normal males underwent lower body negative pressure at -15 mmHg for 90 min, a maneuver that deactivates cardiopulmonary baroreceptors. Glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and filtration fraction (FF) were measured in eight of these subjects using inulin and p-aminohippuric acid clearance techniques. During reduction of central venous pressure, arterial blood pressure and heart rate did not change. Plasma concentrations of atrial natriuretic factor (ANF) decreased markedly (22 +/- 2 to 12 +/- 1 pg/ml, P = 0.0001) as did the second messenger of ANF's biological action, guanosine 3',5'-cyclic monophosphate, whereas renin and vasopressin were not significantly altered. There was a significant rise in plasma norepinephrine (1.6 +/- 0.2 to 2.4 +/- 0.4 nmol/l, P = 0.03). GFR (104 +/- 9 to 68 +/- 6 ml/min, P = 0.007) and FF (0.18 +/- 0.01 to 0.14 +/- 0.01, P = 0.007) decreased significantly, with maintenance of ERPF. There was a significant antinatriuresis without an antikaliuresis and a significant reduction in free water clearance. These changes in renal hemodynamics are unlike the known effects of renal vasoconstrictors, and the alterations in solute and free water clearance are consistent with the removal of the known actions of ANF from tubular target sites. Taken together, our findings suggest that a mechanism other than activation of vasoconstrictors, possibly the diminution of the influence of ANF on the kidney, may be operative in the renal adjustments to cardiopulmonary baroreflex deactivation in humans.

Effects of gonadectomy on sexually dimorphic antidiuretic action of vasopressin in conscious rats

1994 ◽  
Vol 267 (2) ◽  
pp. R536-R541 ◽  
Author(s):  
Y. X. Wang ◽  
J. T. Crofton ◽  
H. Liu ◽  
D. P. Brooks ◽  
L. Share
Keyword(s):  
Estrous Cycle ◽  
Urine Volume ◽  
Free Water ◽  
Female Rats ◽  
Intact Male ◽  
Free Water Clearance ◽  
Urinary Osmolality ◽  
Arterial Blood ◽  
Antidiuretic Action ◽  
Water Clearance

The present study examined whether the antidiuretic response to vasopressin is affected by the estrous cycle and by gonadectomy in conscious, chronically instrumented hydrated rats. Infusion of vasopressin (10-100 pg.min-1.kg body wt-1) resulted in a dose-dependent antidiuresis. Urine volume and free water clearance decreased and urinary osmolality increased with no significant changes in mean arterial blood pressure, heart rate, osmolar clearance, and urinary sodium and potassium excretion. The antidiuretic response to vasopressin was significantly greater in intact male and estrous female rats than in intact female rats in the other phases of the estrous cycle. Thus the calculated doses of vasopressin to reduce urine flow and free water clearance, as well as to increase urinary osmolality 50% from their control values, were significantly higher in nonestrous females than in males and estrous females. Gonadectomy was without effect on the antidiuretic potency of vasopressin in males, but in gonadectomized females the antidiuretic response to vasopressin was enhanced to a level similar to that observed in intact males. These data indicate that the antidiuretic activity of vasopressin is affected not only by gender but also by phase of the estrous cycle and that the ovarian hormone(s) may modulate the antidiuretic action of vasopressin.

Metabolic and renal effects of acute hypercalcemia in dogs

1961 ◽  
Vol 200 (2) ◽  
pp. 359-366 ◽  
Author(s):  
Stanley Wallach ◽  
Anne C. Carter
Keyword(s):  
Glomerular Filtration ◽  
Renal Plasma Flow ◽  
Free Water ◽  
Calcium Content ◽  
Plasma Calcium ◽  
Free Water Clearance ◽  
Renal Effects ◽  
Tubular Transport ◽  
Solute Excretion ◽  
Water Clearance

The acute metabolic and renal effects of exogenously produced hypercalcemia were studied in hydrated dogs ingesting high- and low-calcium diets, in parathyroidectomized dogs and in dogs receiving vitamin D2. Under all these conditions, elevation of the plasma calcium concentration to 18 mg/100 ml resulted in solute diureses containing all major cations and in hyperphosphatemia. No change in free water clearance or net tubular transport of phosphorus occurred. Further elevation of levels of the plasma calcium caused marked reductions of glomerular filtration, renal plasma flow, and solute excretion and an increase in free water clearance. The increment in cation excretion exceeded the quantity of calcium retained. Less than 50% of the calcium load could be located in the extracellular space and urine at the end of the infusions. Erythrocyte calcium content increased two- to fourfold but erythrocyte concentrations of magnesium and acid-soluble phosphorus did not change. These data suggest that the solute diuresis of hypercalcemia is primarily renal in origin. Displacement of cations from osseous and intracellular sites by calcium may also occur and contribute to the solute diuresis. The hyperphosphatemia is independent of changes in parathyroid function, glomerular filtration and tubular transport of phosphorus and constitutes an unexplained consequence of induced hypercalcemia.

scholarly journals Phenotyping nocturnal polyuria: circadian and age-related variations in diuresis rate, free water clearance and sodium clearance

2020 ◽  
Vol 49 (3) ◽  
pp. 439-445 ◽  
Author(s):  
Thomas F Monaghan ◽  
Donald L Bliwise ◽  
Marie-Astrid Denys ◽  
An-Sofie Goessaert ◽  
Veerle Decalf ◽  
...  
Keyword(s):  
Linear Models ◽  
Age Groups ◽  
Free Water ◽  
Time Of Day ◽  
Nocturnal Polyuria ◽  
Free Water Clearance ◽  
Age Related ◽  
Urine Production ◽  
Sodium Clearance ◽  
Water Clearance

Abstract Background this study compares diuresis rate, sodium clearance and free water clearance (FWC) by age and time of day (nighttime vs. daytime) in subjects with and without nocturnal polyuria (NP) to determine whether these variables affect the phenotype of NP. Methods post hoc analysis of two prospective observational studies. Eight urine samples collected at 3-h intervals and a single blood sample were used to calculate daytime (10a/1p/4p/7p/10p) and nighttime (1a/4a/7a) diuresis rates, sodium clearance and FWC. Three mixed linear models were constructed for diuresis rate, sodium clearance and FWC using four predictor variables: NP status (present [nocturnal urine production &gt;90 ml/h] vs. absent [≤90 ml/h]), time of day, age and study identification. Results subjects with NP experienced higher nighttime versus daytime diuresis rates, sodium clearance and FWC. Regardless of NP status, increased age was accompanied by an increase in the ratio of nighttime/daytime diuresis rate, nighttime sodium clearance and daytime sodium clearance. FWC showed a complex age effect, which was independent of time of day or NP status. Conclusions age-related increases in nighttime/daytime diuresis rate, 24-h sodium clearance and 24-h FWC are not specific to subjects with NP. The age-related surge in either nocturnal sodium clearance or nocturnal FWC may represent the relevant substrate for behavioural or pharmacologic interventions targeting sodium diuresis or free water diuresis, respectively. Increases in FWC in older age groups may reflect impaired circadian rhythmicity of endogenous AVP or changes in responsiveness of the aged nephron to water clearance.

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