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PubMed1985

Abnormal pressure-diuresis-natriuresis response in spontaneously hypertensive rats.

The renal responses to changes in perfusion pressure (RPP) were studied in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) to determine whether an abnormality in the pressure-diuresis phenomenon could be involved in the resetting of kidney function in hypertension. Differences in the neural and endocrine background to the kidneys were minimized by denervating the kidney and by holding plasma vasopressin, aldosterone, corticosterone, and norepinephrine levels constant by intravenous infusion. In WKY, increasing renal perfusion pressure 54 mmHg, from 103 to 157 mmHg, produced a ninefold increase in urine flow and sodium excretion with no measurable change in renal blood flow (RBF) or glomerular filtration rate (GFR). In SHR, increasing renal perfusion pressure 54 mmHg, from 133 to 187 mmHg, produced only a fourfold increase in urine flow and sodium excretion. GFR, RBF, and peritubular capillary pressures were well autoregulated and were similar in the SHR and WKY at pressures above 110 mmHg. These results indicate the presence of intrinsic changes in the kidney of SHR that enhance fractional tubular reabsorption and impair the pressure-diuresis response. This blunting of the renal pressure-diuresis phenomenon in SHR may represent the functional resetting of the kidney that is necessary for sustained hypertension.

Animals↗
PubMed1993

Osmotic adaptation of renal medullary cells during transition from chronic diuresis to antidiuresis.

The cells of the renal medulla adapt osmotically to high extracellular tonicities by high concentrations of organic osmolytes. Intracellular accumulation of these substances is, however, relatively slow. The aim of the present study was to assess the effect of an abrupt rise in extracellular tonicity on intracellular osmotically active substances after prior reduction of medullary contents of organic osmolytes by chronic diuresis. Intra- and extracellular electrolyte concentrations at the papillary tip and the tissue contents of methylamines (glycerophosphorylcholine, betaine), polyols (myo-inositol, sorbitol), and several amino acids were determined in the different kidney zones by electron microprobe analysis and high-performance liquid chromatography in control animals, in rats infused for 6 days with furosemide via osmotic minipumps, and in rats given the vasopressin analogue [deamino-Cys1,D-Arg8]vasopressin (DDAVP) after the chronic furosemide treatment. Chronic diuresis greatly reduced interstitial tonicity and inner medullary contents of methylamines and polyols and moderately reduced inner medullary amino acid contents but did not significantly affect intracellular electrolyte concentrations. When the diuretic rats were infused with DDAVP for 2 h, interstitial tonicity more than doubled and intracellular K and Cl concentrations rose by approximately 60 and 160%, while inner medullary contents of methylamines, polyols, and amino acids were not changed significantly. These data demonstrate that after effective depletion of medullary organic osmolytes by long-term diuresis, the cells of the renal papilla adapt osmotically to an abrupt increase in extracellular tonicities by elevated cell electrolyte concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine↗
PubMed1992

Vasopressin inhibits diuresis induced by water immersion in humans.

We tested the hypothesis that 1-desamino-8-D-arginine vasopressin (DDAVP), a V2-receptor agonist, could inhibit the diuresis induced by water immersion in humans. Water and electrolyte excretion, plasma atrial natriuretic factor concentration, and plasma aldosterone concentration were measured initially and after 3 h of water immersion in 13 healthy sodium-replete men given either placebo or 20 micrograms of intranasal DDAVP. Guanosine 3',5'-cyclic monophosphate and urea excretion and urine osmolality were also determined. DDAVP inhibited the diuresis induced by water immersion in men: 758 +/- 168 (SE) ml/3 h in the placebo group vs. 159 +/- 28 ml/3 h in the DDAVP group (P less than 0.05). After 3 h of water immersion, plasma atrial natriuretic factor concentrations were increased from 11 +/- 2 to 20 +/- 4 pg/ml in the placebo group and from 14 +/- 2 to 33 +/- 4 pg/ml in the DDAVP group (P less than 0.05). Plasma aldosterone concentrations were decreased from 98 +/- 18 to 45 +/- 6 pg/ml in the placebo group (P less than 0.05) and from 54 +/- 17 to 25 +/- 5 pg/ml in the DDAVP group (P less than 0.05). Despite these changes in aldosterone and atrial natriuretic factor concentrations, which should increase sodium excretion, DDAVP decreased the natriuresis induced by water immersion in humans: 56 +/- 8 meq Na+/3 h in the placebo group vs. 36 +/- 6 meq Na+/3 h in the DDAVP group (P less than 0.05). DDAVP may be used to prevent the diuresis associated with central redistribution of blood volumes that occur during water immersion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2003

Effects of forced diuresis achieved by oral hydration and oral diuretic administration on uroflowmetric parameters and clinical waiting time of patients with lower urinary tract symptoms.

INTRODUCTION: We studied the impact of diuresis forced by oral hydration or single-dose oral diuretic administration on uroflowmetric parameters and clinical waiting time of patients with lower urinary tract symptoms. PATIENTS AND METHODS: A total of 58 patients with a mean age of 59 (range 41-77) years who presented with lower urinary tract symptoms were included in the study. The patients were grouped with respect to their International Prostate Symptom Scores as having mild, moderate, or severe symptoms. The prostatic volumes of the patients were calculated using transrectal ultrasound. Uroflowmetric measurements were performed on 3 consecutive days. On the 1st day, the test was performed without diuretic stimulation; on the 2nd day, oral hydration was applied, and on the 3rd day, the patients received 20 mg of furosemide orally. Voiding time, maximum flow rate, voided volume, and the time elapsed in minutes until voiding (waiting time) were recorded. RESULTS: Diuretic stimulation did not significantly alter the uroflowmetric parameters in each symptom group, but the waiting time was significantly reduced. Forced diuresis caused acute urinary retention in 5 of 20 (25%) severely symptomatic patients. CONCLUSIONS: Forced diuresis with oral hydration or oral administration of diuretics improves patient comfort and test applicability by shortening clinical waiting time and reducing the number of attempts to reach the sufficient urine volume for reliable measurements and can be applied safely for mild and moderately symptomatic patients. On the other hand, the risk of 25% of acute urinary retentions should be reconsidered, and the decision about diuretic stimuli should be made carefully by the clinician in severely symptomatic patients.

Administration, Oral↗
PubMed1986

Effects of furosemide diuresis on mercuric chloride-induced acute renal failure in the rat.

In previous studies in rats given mercuric chloride (HgCl2), administration of furosemide has been found to either attenuate, exacerbate, or not affect the severity of the acute renal failure (ARF) otherwise expected to obtain. In the current study in rats given large doses of furosemide and in which urinary fluid losses were replaced by intravenous infusions of saline, administration of HgCl2 induced less severe ARF than that induced in rats not given furosemide and saline infusions. In rats not given furosemide, a diuresis induced by continuous reinfusion of urine also conferred protection against the nephrotoxic effect of HgCl2. These findings suggest that in rats given HgCl2: diuresis per se is the critical determinant of any salutary effect of furosemide and the protective effect of diuresis does not depend on renal elimination of mercury.

Acute Kidney Injury↗
PubMed1992

Post-obstruction diuresis: influence of renal prostaglandins.

The possible role of altered renal prostaglandin metabolism in the generation of post-obstruction diuresis (POD) was examined in 16 adult male Sprague-Dawley rats. Inhibition of cyclooxygenase by the administration of a combination of two nonsteroidal anti-inflammatory drugs (NSAID), meclofenamate and indomethacin in 8 of these rats exaggerated, rather than lowered the degree of natriuresis and diuresis that followed the release 24 h after bilateral ureteral ligation. Urine osmolarity was similar in the two groups of rats treated with the NSAID and vehicle. The results suggest an enhanced synthesis of renal vasoconstrictor and antidiuretic prostaglandins (thromboxane A2 or PGF2 alpha) during bilateral ureteral ligation. NSAIDs such as aspirin, indomethacin, meclofenamate and others may promote POD by blocking this prostaglandin pathway while promoting the cytochrome P450 monooxygenase pathway which may produce vasodilator, diuretic and natriuretic paracrine hormones. Additionally, inhibition of prostaglandin synthesis may have enhanced post-obstruction diuresis in the present studies by allowing a greater volume expansion during obstruction, as indicated by a reduced hematocrit in the rats that were pretreated with NSAID.

Analysis of Variance↗
PubMed1985

Role of the diuresis renogram in the study of the pelviureteric junction.

A consecutive series of 29 patients (33 pelviureteric units) with urographic signs of altered passage through the pelviureteric junction underwent diuresis renography performed by means of an intravenous injection of 99mTc-diethylenetriamine pentaacetic acid/kg body weight followed by intravenous administration of frusemide. Anderson-Hynes pyeloplasty was performed in 19 pelviureteric units with a modest or almost absent fall in the renographic curve after diuretic injection; 2 other symptomatic patients, in whom a moderate fall of the same curve was found also underwent surgery. Complete normalization of the renogram was observed in 17 of 21 operated patients. Severe functional deficit and polymegacalicosis were evident in 3 and 1 patient, respectively, with unchanged postoperative renograms. During follow-up (6 months to 2 years) diuresis renography remained unaltered in non-operated units. Our experience indicates how the diuresis renogram not only gives functional confirmation of a pelviureteric junction obstruction, but is also helpful in resolving situations in which there is a discrepancy between symptoms and urographic signs. Furthermore it provides an accurate method for evaluating the results of pyeloplasty. However, the use of this investigation is not, in our opinion, indicated in the presence of severe functional deficit of the kidney or pyelectasis.

Adolescent↗
PubMed1997

A peptide released by pepsin from kininogen domain 1 is a potent blocker of ANP-mediated diuresis-natriuresis in the rat.

A 20-amino acid peptide, KYEIKEGDCPVQSGKTWQDC (PU-D1), released by pepsin hydrolysis of LMW kininogen domain 1 was tested for its ability to antagonize the diuretic and natriuretic effect of ANP(103-125) in anesthetized rats. A single dose of 10.8 or 21.6 pmol (25 or 50 ng) PU-D1 given intravenously or into the duodenal lumen suppressed the diuresis-natriuresis induced by 209 pmol (500 ng) ANP by 43% to 59% and 69% to 96%, respectively. None of the doses tested (2.16 to 432 pmol, 5 ng to 1 microg) modified systemic blood pressure. Strikingly, a single IV dose of 10.8 pmol PU-D1 blocked the action of ANP for more than 3 hours. ANP blockade by PU-D1 was annulled completely by the bradykinin (BK) B2 receptor inhibitor Hoe 140. On a molar basis, PU-D1 is more effective than BK and kinins of 15, 16, and 18 amino acids for blocking the ANP-mediated diuresis-natriuresis. As with BK and other kinins, the inhibitory effect of Pu-D1 on ANP is obtained only within a small range of picomol doses. A single dose of 2.16 or 4.32 pmol PU-D1 or 47 pmol (50 ng) BK is ineffective against ANP if injected alone. However, when both substances are administered concomitantly at these subthreshold doses, they totally suppress ANP-induced diuresis-natriuresis. These results raise the question of whether PU-D1, released from kininogen domain 1, either alone or associated with BK, may interact with ANP in the regulation of urinary water and electrolyte excretion in physiological and pathological conditions.

Amino Acid Sequence↗
PubMed1985

Relaxation of lower esophageal sphincter and stimulation of gastric secretion and diuresis by antiasthmatic xanthines. Role of adenosine antagonism.

The study was designed to obtain information on selected extrapulmonary effects of enprofylline, an adenosine-non-blocking alkylxanthine that is about 5 times more potent as a bronchodilator than the adenosine receptor antagonist theophylline. Effects of theophylline (5.0 mg/kg) on lower esophageal sphincter pressure (LESP), gastric secretion, and diuresis and of enprofylline (1.5 mg/kg intravenously producing about 2 micrograms/ml plasma) were examined in 8 healthy volunteers. Enprofylline and theophylline decreased LESP (by 5.0 +/- 2.6 mm Hg, mean +/- SD, p less than 0.001, and by 5.8 +/- 2.7 mmHg, p less than 0.001, respectively), but only theophylline stimulated gastric secretion (volume p less than 0.01 and acidity p less than 0.01) and urine production (volume p less than 0.01 and sodium chloride excretion p less than 0.01). Neither xanthine affected plasma gastrin. Enprofylline and theophylline can be expected to have a similar ability to reduce the barrier to gastroesophageal reflux, but only the latter would have additional stimulant effects on gastric secretion and diuresis. These findings may have clinical significance and suggest a role for adenosine in regulating gastric secretion (and diuresis) but not LESP.

Adult↗
PubMed1970

On the role of antidiuretic hormone in the inhibition of acute water diuresis in adrenal insufficiency and the effects of gluco- and mineralocorticoids in reversing the inhibition.

In order to determine whether or not antidiuretic hormone (ADH) is essential to the inhibition of an acute water diuresis in adrenal insufficiency, the response to oral water loads was tested in rats with hereditary hypothalamic diabetes insipidus (DI) which lack ADH. It was found that 60 min after water loads of 3 or 5% of body weight urine flow was significantly lower and urine osmolality significantly higher in adrenalectomized DI rats than in the same DI rats before removal of their adrenal glands. The efficacy of gluco- and mineralocorticoids in reversing the inhibition was then determined in the same adrenalectomized DI rats. Prednisolone alone, administered either acutely or chronically, restored the response in urine flow to that seen in the same rats before adrenalectomy, but failed to correct the defect in urinary dilution. Aldosterone when given alone tended to correct the diluting ability but not the response in urine flow. When these two adrenal cortical hormones were given simultaneously, both the urine flow and urine osmolality were nearly identical to what they had been in the same DI rats before adrenalectomy. These studies strongly suggest (a) that ADH is not essential to the inhibition of an acute water diuresis in adrenal insufficiency, although it may abet the inhibition in individuals without diabetes insipidus, which can elaborate ADH; and (b) that both gluco- and mineralocorticoids are required in adrenal insufficiency in order to fully restore the water diuresis as judged by the dual criteria of urine flow and urine osmolality.

Adrenal Glands↗
PubMed1997

Anti-diuresis in the blood-feeding insect Rhodnius prolixus Stål: the peptide CAP2b and cyclic GMP inhibit Malpighian tubule fluid secretion.

Rhodnius prolixus eliminates NaCl-rich urine at high rates following its infrequent but massive blood meals. This diuresis involves stimulation of Malpighian tubule fluid secretion by diuretic hormones released in response to distention of the abdomen during feeding. The precipitous decline in urine flow that occurs several hours after feeding has been thought until now to result from a decline in diuretic hormone release. We suggest here that insect cardioacceleratory peptide 2b (CAP2b) and cyclic GMP are part of a novel mechanism of anti-diuresis. Secretion rates of 5-hydroxytryptamine-stimulated Malpighian tubules are reduced by low doses of CAP2b or cyclic GMP. Maximal secretion rates are restored by exposing tubules to 1 mmol l-1 cyclic AMP. Levels of cyclic GMP in isolated tubules increase in response to CAP2b, consistent with a role for cyclic GMP as an intracellular second messenger. Levels of cyclic GMP in tubules also increase as urine output rates decline in vivo, suggesting a physiological role for this nucleotide in the termination of diuresis.

Animals↗
PubMedDate not supplied

Acid and alkaline diuresis. When are they of value in the treatment of poisoning?

The utility of both acid and alkaline diuresis has been brought into question because of the ability to increase the elimination rate of many toxins by less care-intensive methods such as repeated-dose charcoal. Alkaline diuresis is a technique which uses a common drug, but acid diuresis is not a technique known to most physicians. The former is currently the best therapy for quinine poisoning. Phencyclidine elimination is increased by 10%, but most patients recover with only supportive care. Acidification has been effective in some hands; data suggest that renal elimination is not the only mechanism of action of this therapy. In deeply comatose patients with hypotension, acidification should be considered. Alkalinisation, the mainstay of therapy for salicylate and phenobarbital poisoning over many decades, is effective, although no more so than charcoal, and less than dialysis.

Acids↗
PubMed1994

Reversibility of diabetes- and diuresis-induced alterations in rat bladder dome muscarinic receptors.

Previous studies from our laboratory demonstrated that 8 weeks of streptozocin (STZ)-induced diabetes and sucrose-fed diuresis resulted in increases in the density of muscarinic receptors in rat bladder dome and that early insulin treatment (started 3 days after the onset of diabetes) prevented the diabetes-induced upregulation (J Pharmacol Exp Ther 248:81-88, 1989; Diabetes 40: 1150-1156, 1991; J Urol 147:760-763, 1992). To determine whether diabetes- and diuresis-induced alterations in muscarinic receptors in rat bladder dome are reversible, we administered insulin (beginning 8 weeks after the onset of diabetes) or removed sucrose from drinking water of diuretic rats (beginning 8 weeks after the onset of diuresis). Five groups of rats were maintained for 16 weeks: 1) STZ-induced diabetic rats (65 mg/kg intravenously); 2) insulin-treated diabetic rats (5-8 U/day insulin subcutaneously beginning 8 weeks after the onset of diabetes); 3) sucrose-fed diuretic rats (5% sucrose in drinking water throughout 16 weeks); 4) sucrose-removed rats (sucrose withdrawn from drinking water after 8 weeks of the sucrose-induced diuretic state); and 5) age-matched control rats. Radioligand receptor binding experiments with [3H]quinuclidinyl benzilate showed an increase in the density of muscarinic receptors in bladder dome of diabetic and sucrose-fed rats compared with age-matched control rats. Removing the 5% sucrose from the drinking water of diuretic rats reversed the increased water intake and urine output, decreased the bladder hypertrophy that accompanied the diuretic state, and corrected the upregulation of the muscarinic receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2002

Effect of diabetes on renal medullary oxygenation during water diuresis.

OBJECTIVES: To study the effect of water diuresis on renal medullary and cortical oxygenation in patients with diabetes using blood oxygenation level--dependent magnetic resonance imaging (BOLD MRI). RESEARCH DESIGN AND METHODS: Nine mild diabetic subjects (48 +/- 2.7 years of age, six women) and nine nondiabetic subjects of similar age and sex, all without known vascular or renal disease, were studied noninvasively by MRI before and during water diuresis. RESULTS: Water diuresis induced an increase in medullary oxygenation in control subjects, producing a decrease in R2* (apparent spin-spin relaxation time) of 1.89 +/- 0.27 (P < 0.01), but no significant change in the group of diabetic subjects. CONCLUSIONS: These findings in middle-aged diabetic subjects, which resembled those previously described in elderly subjects >65 years of age, suggest early impairment of adaptive vasodilatation within the renal medulla in diabetes.

Adult↗
PubMed1986

High pressure diuresis initiates malignant hypertension in the young.

Weight loss, polydipsia, polyuria, hyponatremia are symptoms often seen in patients with severe renin-induced hypertension. To investigate the role of the maturing kidney in the development of high pressure diuresis hypertension was induced in infantile (18 days old) and adult (40 days old) Sprague-Dawley rats by clipping one renal artery. In infantile rats blood pressure increase was steeper than in adult rats (7.8 vs. 3.2 mmHg/day). High pressure diuresis resulting in body weight loss was observed at systolic blood pressure levels of about 140 to 150 mmHg in infantile animals compared to 180 mmHg in adult rats. At this time fluid intake was increased to 64 in infantile and 30 ml/100 g body weight/day in adult rats. Plasma renin concentration and aldosterone were two fold higher in infantile than in adult rats. The data show that infantile rats, due to a higher activation of the renin-angiotensin-aldosterone system, have a steeper blood pressure increase and, furthermore, that during maturation of the kidney high pressure diuresis starts at lower blood pressure levels and is much more pronounced.

Age Factors↗
PubMed2006

Renal adrenomedullin and high altitude diuresis.

Previous investigations revealed that most of the fluid regulating hormones showed no consistent relationship to the hypoxic diuretic response (HDR). In this study we examined if adrenomedullin (AM), a hypoxia-mediated diuretic/natriuretic peptide is connected to HDR. Thirty-three persons were examined at low altitude (LA), on the third exposure day at 3440 m (medium altitude, MA) and on the fourteenth day at 5050 m (high altitude, HA). Nocturnal diuresis rose from 460 ml [interquartile range 302 ml] at LA to 560 [660] ml at MA to 1015 [750] ml at HA (p<0.005). Sodium excretion was similar at LA and MA (41.8 [27.0] vs. 41.4 [28.4] mM) and increased to 80.2 [29.1] mM at HA (p<0.005). Urinary AM excretion was 7.9 [3.9] at LA, 7.5 [5.7] pM at MA, and increased to 10.5 [5.1] pM (p<0.05) at HA. Urinary AM excretion was correlated to diuresis (r=0.72, p<0.005) and sodium excretion (r=0.57, p<0.005). Plasma AM concentration rose from 16.4 [3.1] to 18.8 [4.9] pM/l at MA (p<0.005) and to 18.3 [4.3] pM/l at HA (p<0.005). Plasma AM concentration and urinary AM excretion were not correlated, neither were plasma AM concentration and diuresis or natriuresis. Our data suggest the involvement of increased renal AM production in the pathophysiology of high altitude fluid and sodium loss.

Adrenomedullin↗
PubMed2003

[Long-term followup of water and solute metabolism in intestinal urinary diversion and the effect of diuresis; a 4-years observation in a unilateral ileal conduit model in dog].

PURPOSE: An intestinal segment interposed in the urinary tract can influence the water-solute balance of the patients with urinary diversion. It seems necessary to know whether such influence is changeable with the lapse of time and is also important to know whether diuresis is beneficial or not to minimize the effect of intestinal urinary diversion. MATERIALS & METHODS: In 8 female mongrel dogs a unilateral ileal conduit urinary diversion was constructed in the right nephroureteral units using a 20 cm segment of the ileum. After two months, separate urine for exactly 3 hours was collected from the conduit stoma and the bladder catheter, and analysis was made on each solute in the urine. In 4 dogs surviving for 4 years with stable renal function the examinations were repeated to compare with previous results. Furthermore, the effect of diuresis on the water and solute excretion was examined using 6 dogs. RESULTS: Water was reabsorbed or excreted from the ileal conduit according to the osmolality of the urine. No significant change was observed 4 years after operation. Urinary solute excretion and osmolality of the diverted side were always lower than those of intact side throughout the period. Creatinine clearance was not influence by the interposition of an ileal segment in the urinary tract in any periods. Excretion of water and reabsorption of solute was accelerated under oliguric condition and significant reabsorption of creatinine was observed in this condition. CONCLUSION: In the experimental observation using canine model with unilateral ileal conduit urinary diversion no significant differences were observed in water and solute metabolism between the early period and 4 years after operation. Diuresis appeared to be favorable to minimize the reabsorption of urinary solute from the ileal conduit.

Animals↗
PubMed1976

Percutaneous intrapelvic pressure registration in hydronephrosis during diuresis.

Percutaneous registration of renal pelvis pressure was undertaken successfully in 17 of 22 patients with unilateral hydronephrosis. Intrapelvic pressure was registered continuously during diuresis induced by mannitol and Urografin. In 10 cases additional increase in urine flow was induced by administration of furosemide. Ureteric urine flow was recorded through a cystoscopically introduced catheter on the side under investigation in 7 cases. The basic pressure was on average 12 mmHg and more than 20 mmHg in 2 cases only. No correlation was found between baseline pressure and degree of hydronephrosis. The intrapelvic pressure rose during forced diuresis with a few exceptions within normal limits. No correlation was demonstrated between pressure rise and renographically estimated kidney function. Pelvic peristaltic activity was detectable in only 3 cases. It is concluded that preoperative registration of renal pelvic pressure during diuresis as performed in this study is of no value in selection of the method of treatment in patients with hydronephrosis.

Adolescent↗