atrial-natriuretic-factor and Water-Intoxication

The simultaneous time courses of hydromineral hormones (renin-aldosterone system, arginine vasopressin, and atrial natriuretic peptide) and renal responses were examined during and after the completion of hyperhydration induced by glycerol and fluid ingestion. Eight healthy young male Caucasian subjects participated in two separate trials, each including three consecutive phases in a thermoneutral environment. Phases 1 and 3 involved a 90-min period at rest, while phase 2 involved a 120-min period at rest designed to provide either (i) euhydration (control trial) or (ii) hyperhydration induced by ingestion of glycerol (1.1 g/kg body mass) and fluid (21.4 mL/kg body mass). During the 2-h time period of glycerol and fluid ingestion, urine flow, urine osmolality, and plasma levels of hydromineral hormones remained at basal values. In contrast, after hyperhydration completion during phase 3, the diuresis increased markedly together with a dilution of the urine (p < 0.05) while hormonal responses did not change. These results indicate significant differences in renal responses during and after hyperhydration completion and suggest that these changes are independent of fluid-regulating hormonal responses.

Topics: Adult; Aldosterone; Algorithms; Arginine Vasopressin; Atrial Natriuretic Factor; Body Weight; Electrolytes; Glomerular Filtration Rate; Glycerol; Hormones; Humans; Kidney; Male; Osmolar Concentration; Renin; Urodynamics; Water Intoxication; Water-Electrolyte Balance

Brain natriuretic peptide (BNP) is released into circulation in response to ventricular dilatation and pressure overload. Plasma BNP concentration correlates with left ventricular mass and dysfunction, which is prevalent in hemodialysis (HD) patients.. To evaluate the potential of BNP level for determination of hydration status, we measured inferior vena caval diameter (IVCD) and BNP levels and performed bioimpedance analysis in 49 HD patients.. Pre-HD BNP levels remained unchanged after HD. Agreement between IVCD and pre-HD BNP level in overhydration was significant (kappa = 0.304). The area under the receiver operating characteristic (ROC) curve for overhydration was 0.819 for pre-HD BNP level. When extracellular fluid/total-body water (ECF/TBW) ratios of HD patients were compared with those of 723 controls, pre- and post-HD BNP levels were significantly greater in overhydrated patients. The area under the ROC curve for overhydration by ECF/TBW ratio was 0.781 for pre-HD BNP level. However, there was no significance for pre- or post-HD BNP levels on assessment of normohydration or underhydration. Pre-HD BNP level correlated significantly with post-HD BNP level, post-HD diastolic blood pressure, pulse pressure, and ECF/TBW ratio. IVCD correlated significantly with post-HD BNP level.. BNP level seems to have a limited potential for assessment of overhydration in HD patients.

Topics: Adult; Aged; Atrial Natriuretic Factor; Biomarkers; Body Water; Cyclic GMP; Diabetic Nephropathies; Electric Impedance; Extracellular Fluid; Female; Humans; Kidney Failure, Chronic; Male; Middle Aged; Natriuretic Peptide, Brain; Renal Dialysis; ROC Curve; Sensitivity and Specificity; Ultrasonography; Vena Cava, Inferior; Ventricular Dysfunction, Left; Water Intoxication

Heart failure is a leading cause of morbidity and mortality. In the United States, there are more than 5 million patients with heart failure and over 500,000 newly diagnosed cases each year. Numerous advances have been made in our understanding of the pathophysiologic mechanisms contributing to sodium and water retention in this condition. Important alterations in the sympathetic nervous system and the renin-angiotensin-aldosterone system have been described in heart failure, allowing the use of mechanism-specific treatments such as beta-adrenergic receptor antagonism and angiotensin-converting enzyme inhibition. As our understanding of the roles of the natriuretic peptides and the arginine vasopressin-aquaporin-2 system in the pathophysiology of heart failure evolves, treatments directed toward the alterations in these systems in heart failure can be further developed.

Topics: Adrenergic beta-Antagonists; Angiotensin-Converting Enzyme Inhibitors; Atrial Natriuretic Factor; Body Fluids; Heart Failure; Humans; Natriuretic Peptide, Brain; Neurosecretory Systems; Renin-Angiotensin System; Sodium; Sympathetic Nervous System; Vasopressins; Water Intoxication; Water-Electrolyte Imbalance

Polydipsia-hyponatremia is a poorly understood disorder that causes considerable mortality and morbidity. Hyponatremia in polydipsia-hyponatremia has been attributed to disturbances in antidiuretic hormone (ADH) function. Improvements in polydipsia-hyponatremia during clozapine treatment offered the chance to see if levels of ADH and other hormones associated with osmoregulation changed with improvement in biochemical and clinical measures of polydipsia-hyponatremia.. In this preliminary, longitudinal study, we studied 2 male schizophrenic patients (DSM-III-R) who had polydipsia-hyponatremia. Measures were (1) biochemical and clinical: serum sodium and osmolality, urine osmolality and specific gravity, normalized diurnal weight gain, and estimated urine volume and (2) endocrine: ADH, angiotensin II, atrial natriuretic peptide, and prolactin. Measures were collected during 2 months of baseline (typical neuroleptic) and 6 months of clozapine treatment.. Single-case statistical procedures showed significant changes in sodium levels (a.m. and p.m.), estimated urine volume, and a.m. urine specific gravity in both patients and significantly decreased diurnal weight gain in 1 patient. Both serum and urine osmolality showed improvement, but values did not reach statistical significance. Low baseline ADH levels persisted through 6 months of clozapine treatment and showed no changes in the context of improvements in serum sodium and osmolality. No significant changes were seen in levels of angiotensin II and atrial natriuretic peptide.. Given the limitations of this study, there is some evidence to suggest that the improvements in serum sodium and osmolality during clozapine treatment of polydipsia-hyponatremia may not be related to serum levels of ADH, although altered ADH receptor function cannot be ruled out. These data need to be extended in larger samples.

Topics: Adult; Angiotensin II; Atrial Natriuretic Factor; Circadian Rhythm; Clozapine; Humans; Hyponatremia; Longitudinal Studies; Male; Middle Aged; Osmolar Concentration; Prolactin; Schizophrenia; Sodium; Urine; Vasopressins; Water Intoxication

The density of the lung reflects the total mass of fluid, air, and dry lung tissue per unit volume of the lung. Lung density can be measured by evaluation of attenuation of an electron beam with computed tomography (CT). This technique has been shown to be sufficiently reliable and sensitive to distinguish normal from abnormal lung water. The aim of this study was to find out whether lung density properly reflects the hydration status in hemodialysis patients in comparison with other standard methods. Fourteen hemodialysis patients, with an ultrafiltration ranging from 0.3 to 4.5 liters per session, underwent CT measurements of lung density, ultrasonographic measurements of the diameter of the inferior vena cava after quiet expiration (IVCe) and quiet inspiration (IVCi), and measurements of the hematocrit and plasma levels of the biochemical hydration markers cyclic guanosine monophosphate (cGMP) and atrial natriuretic peptide (ANP). These measurements were performed before and 3.5 to 4 hours after termination of dialysis. Quantitative estimates of lung density were obtained within pixels with CT numbers ranging between -1000 and -100 Hounsfield Units (HU), and compared with normal data from 18 normal controls. In normal controls, the lung density ranged from -800 to -730 HU. In hemodialysis patients, lung density was significantly higher than normal before dialysis (-678 +/- 96 HU, P < 0.01) and significantly decreased after dialysis (-706 +/- 92 HU, P < 0.05), indicating a decrease in fluid content of the lung. The density was normalized in 5 patients. A significant correlation was found between lung density and IVCe both before and after dialysis (r = 0.8, P < 0.01 for both). Change in density was significantly correlated to amount of ultrafiltration (r = 0.67, P < 0.01) and percent change in blood volume (r = 0.63, P < 0.05), indicating that lung density is greatly affected by changes in the extracellular fluid volume, mainly the intravascular volume. In conclusion, lung water reflects the hydration status in hemodialysis patients and can be monitored by measuring the lung density by CT. Accordingly, normalization of lung density can help to achieve a proper dry weight in these patients.

Topics: Adult; Atrial Natriuretic Factor; Cyclic GMP; Dehydration; Electrolytes; Female; Hemodynamics; Humans; Lung; Male; Middle Aged; Renal Dialysis; Tomography, X-Ray Computed; Ultrasonography; Vena Cava, Inferior; Water Intoxication

An old women was in an 8-year-period 9 times admitted to the hospital because of severe mental disturbances. The average serum sodium concentration was 126.25 +/- 2.43 mmol/l at the admissions; it increased to 139.44 +/- 1.40 mmol/l after intravenous infusion of hypertonic solutions accompanied with the disappearance of the mental disturbances. The patient was usually chronically hyponatremic due to the increased water intake and the insufficient water excretion. The latter was induced by the augmented vasopressin levels. The remarkable feature of the syndrome of inappropriate antidiuretic hormone secretion was its association with lowered blood level of atrial natriuretic factor accompanied by sodium, and volume depletion. Discontinuation of the exaggerated water intake resulted in the elimination of the permanent hyponatremia; no episode of water intoxication occurred during the last 3 and 1/2 years.

Topics: Aged; Atrial Natriuretic Factor; Cognition Disorders; Drinking Behavior; Female; Humans; Hyponatremia; Inappropriate ADH Syndrome; Vasopressins; Water Intoxication

To investigate the hypothesis that calcitonin gene-related peptide (CGRP), a potent vasodilator, is an important physiological defence against fluid overload, plasma CGRP concentrations were measured in various degrees of fluid overload in 26 haemodialysis patients, for whom diuresis, mediated by atrial natriuretic peptide (ANP), is not a possible defence mechanism. Plasma CGRP concentrations were positively correlated with the degree of fluid excess (r = 0.815, p = 0.0001) and were significantly higher in 5 patients with severe fluid overload than in those less severely affected (143 [SE 14] vs 52 [11] pmol/l; p less than 0.001). CGRP may be an effective defence against complications of fluid overload since it can increase capitance by vasodilatation.

Topics: Atrial Natriuretic Factor; Calcitonin Gene-Related Peptide; Diuresis; Humans; Renal Dialysis; Water Intoxication