Suppression of ADH during water immersion in normal man

1975 ◽  
Vol 38 (6) ◽  
pp. 1038-1044 ◽  
Author(s):  
M. Epstein ◽  
D. S. Pins ◽  
M. Miller
Keyword(s):  
Water Immersion ◽  
Free Water ◽  
Urine Osmolality ◽  
Time Of Day ◽  
Normal Male ◽  
Free Water Clearance ◽  
Water Handling ◽  
Normal Man ◽  
Male Subjects ◽  
Central Hypervolemia

Since previous studies from this laboratory have demonstrated that the redistribution of blood volume and concomitant relative central hypervolemia induced by water immersion to the neck causes a profound natriuresis and a suppression of the renin-aldosterone system, it was of interest to assess whether the diuresis induced by immersion was mediated by an analogous inhibition of ADH. The effects of water immersion on renal water handling and urinary ADH excretion were assessed in 10 normal male subjects studied following 14 h of overnight dehydration on two occasions, control and immersion. The conditions of seated posture and time of day were identical. During control ADH persisted at or above prestudy values. Immersion resulted in a progressive decrease in ADH excretion from 80.1 plus or minus 7 (SEM) to 37.3 plus or minus 6.3 muU/min (P smaller than 0.025). Cessation of immersion was associated with a marked increase in ADH from 37.3 +/- 6.3 muU/min to 176.6 +/- 72.6 muU/min during the recovery hour (P smaller than 0.05). Concomitant with these changes urine osmolality decreased significantly beginning as early as the initial hour of immersion from 1044 +/- 36 to 542 +/- 66 mosmol/kg H2O during the final hour of immersion (P smaller than 0.001). Recovery was associated with a significant mean increase in Uosm of 190 +/- 40 mosmol/kg H2O over the final hour of immersion (P smaller than 0.001). The suppression of ADH occurred without concomitant changes in plasma tonicity. These studies are consistent with the suggestion that in hydrated subjects undergoing immersion suppression of ADH release contributes to the enhanced free water clearance, which has been previously documented.

Characterization of the Natriuresis Caused in Normal Man by Immersion in Water

1972 ◽  
Vol 43 (2) ◽  
pp. 275-287 ◽  
Author(s):  
M. Epstein ◽  
D. C. Duncan ◽  
L. M. Fishman
Keyword(s):  
Water Immersion ◽  
Control Period ◽  
Free Water ◽  
Fractional Excretion ◽  
Normal Male ◽  
Free Water Clearance ◽  
Fractional Excretion Of Sodium ◽  
Sodium Load ◽  
Proximal Tubular ◽  
Normal Man

1. The effects of 4–6 h of water immersion on the renal excretion of water and electrolytes were studied in thirteen normal male subjects in balance on a constant diet containing 150 mEq of Na and 100 mEq of K per day. Each subject was studied during a control period, consisting of quiet sitting, and during water immersion to the neck. 2. Immersion resulted in a natriuresis beginning within the first hour, with the rate of sodium excretion eventually exceeding that of the control period by 3–4-fold; potassium excretion also increased. Despite a progressively negative water balance during the immersion studies, urine flow was greater during the first 4 h and free water clearance was greater during the first 2 h of immersion than during the control study. 3. The demonstration of a highly significant increase in fractional excretion of sodium during immersion suggests that the natriuresis of water immersion is not attributable to changes in filtered sodium load. 4. The prompt onset of the natriuresis, the concomitant kaliuresis and the fact that aldosterone secretion under the conditions of study was probably already suppressed make it unlikely that the natriuresis of water immersion is mediated solely by decreases in aldosterone activity. 5. The data suggest that the natriuresis caused by water immersion is the result of decreased fractional reabsorption of sodium proximal to the renal diluting site. The mechanism whereby increased proximal tubular sodium rejection occurs in relation to immersion remains unclear.

Effects of water immersion on renal hemodynamics in normal man

1976 ◽  
Vol 41 (2) ◽  
pp. 230-233 ◽  
Author(s):  
M. Epstein ◽  
R. Levinson ◽  
R. Loutzenhiser
Keyword(s):  
Renal Plasma Flow ◽  
Water Immersion ◽  
Renal Perfusion ◽  
Time Of Day ◽  
Renal Hemodynamics ◽  
Normal Male ◽  
Renal Changes ◽  
Normal Man ◽  
Seated Posture ◽  
Male Subjects

Although previous studies have demonstrated that water immersion to the neck (NI) results in a significant natriuresis and diuresis, the mechanisms are incompletely delineated. Since recent studies have demonstrated that NI induces a marked increase in cardiac index, it is possible that, as a consequence, renal hemodynamics may be augmented markedly during NI thereby mediating the encountered renal changes. The present study was undertaken to delineate the effects of NI on renal plasma flow and glomerular filtration rate as assessed by the clearance of PAH (CPAH) and inulin (CIn), respectively. Nine normal male subjects were studied on two occasions, control and NI. The conditions of seated posture and time of day were identical. Immersion did not alter CIn or CPAH at a time when sodium excretion was increasing markedly. The constancy of CPAH during NI suggests that renal blood flow is unaltered and that the natriuresis of NI is mediated independently of alterations in overall renal perfusion. The sluggish decline of a naturiuresis during recovery is consistent with the presence of a humoral factor contributing to the encountered natriuresis.

Characterization of renal response to prolonged immersion in normal man

1980 ◽  
Vol 49 (2) ◽  
pp. 184-188 ◽  
Author(s):  
M. Epstein ◽  
A. G. DeNunzio ◽  
M. Ramachandran
Keyword(s):  
Weight Loss ◽  
Water Immersion ◽  
The Body ◽  
Normal Male ◽  
Immersion Period ◽  
Prolonged Duration ◽  
Normal Man ◽  
Male Subjects ◽  
Central Hypervolemia

During the initial phase of spaceflight, there is a translocation of fluid from the lower parts of the body to the central vascular compartment with a resultant natriuresis, diuresis, and weight loss. Whether this natriuresis and diuresis result in the attainment of a new steady state or whether the circulatory adjustment is incomplete is the subject of continuing controversy. Because water immersion is regarded as an appropriate model for studying the redistribution of fluid that occurs in weightlessness, we carried out an immersion study of relatively prolonged duration in order to characterize the temporal profile of the renal adaptation to central hypervolemia. Twelve normal male subjects underwent an immersion study of 8-h duration in the sodium-replete state. Immersion resulted in marked natriuresis and diuresis which were sustained throughout the immersion period. The failure of that natriuresis and diuresis of immersion to abate or cease despite marked extrcellular fluid volume contraction as evidenced by a mean weight loss of -2.2 ± 0.3 kg suggests that central blood volume was not restored to normal and that some degree of central hypervolemia probably persisted.

Volume-homeostatic mechanisms in humans during a 12-h posture change

1993 ◽  
Vol 75 (1) ◽  
pp. 349-356 ◽  
Author(s):  
P. Norsk ◽  
C. Stadeager ◽  
L. B. Johansen ◽  
J. Warberg ◽  
P. Bie ◽  
...  
Keyword(s):  
Sodium Excretion ◽  
Venous Pressure ◽  
Free Water ◽  
Plasma Renin ◽  
Arterial Pulse ◽  
Free Water Clearance ◽  
Water Handling ◽  
Renal Sodium Excretion ◽  
Male Subjects ◽  
Peak Value

On one day six male subjects underwent an upright seated (SEAT) study, and on another day they were subjected to a head-down tilt of 3 degrees (HDT). Compared with SEAT, HDT induced prompt increases in central venous pressure (CVP) from -0.5 +/- 0.8 to 8.3 +/- 0.3 mmHg (P < 0.001) and in arterial pulse pressure of 8–18 mmHg (P < 0.001). CVP stabilized after 6 h at levels 2.4–2.8 mmHg below the peak value. Simultaneously, renal sodium excretion gradually increased over the initial 5 h of HDT and stabilized at a level approximately 125 mumol/min over that of SEAT (P < 0.001). Urine flow rate and solute free water clearance increased during the initial 2–6 h of HDT (P < 0.001) but returned to the level of SEAT thereafter. We concluded that CVP is slightly reduced over 12 h of HDT and that a clear temporal dissociation exists between renal sodium and water handling. We suggest that the combined effect of the sustained suppressions of plasma renin activity and plasma aldosterone and norepinephrine concentrations constitutes a mechanism of the increase in renal sodium excretion.

Role of atrial natriuretic peptide and urinary cGMP in the natriuretic and diuretic response to central hypervolemia in normal human subjects

1987 ◽  
Vol 65 (10) ◽  
pp. 2076-2080 ◽  
Author(s):  
W. M. Leung ◽  
A. G. Logan ◽  
P. J. Campbell ◽  
T. E. Debowski ◽  
S. B. Bull ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Water Immersion ◽  
Free Water ◽  
Base Line ◽  
Free Water Clearance ◽  
Diuretic Response ◽  
Line Level ◽  
Central Hypervolemia ◽  
Atrial Natriuretic

The response of plasma atrial natriuretic peptide (ANP) and urinary cGMP excretion to central hypervolemia induced by water immersion was assessed twice in five healthy male subjects, once while immersed in water to the neck for 3 h and again on a control day. Plasma ANP and urinary cGMP were measured by radioimmunoassay. Compared with the control day, overall change in plasma ANP on the immersion day was significant (p < 0.05). In response to water immersion, plasma ANP increased from a base-line level of 13.2 ± 3.1 (mean ± SEM) to 24.2 ± 5.5 pg/mL by 0.5 h of immersion and was sustained at that level throughout the immersion period. Plasma ANP returned to the base-line level at 1 h postimmersion. Urinary cGMP excretion increased significantly by 1 h of immersion and was sustained at that level throughout water immersion and 1 h postimmersion (p < 0.05). During water immersion urine flow, urinary sodium and potassium excretion, free water clearance, and osmolar clearance increased while plasma renin activity, serum aldosterone, and blood pressure fell; all changes were significant (p < 0.05). Creatinine clearance and hematocrit did not show any significant changes. These data suggest that an increase in plasma ANP may contribute to the natriuretic and diuretic response to central hypervolemia, and that the measurement of urinary cGMP may be a valuable marker of ANP biological responsiveness.

Role of ANP in natriuresis of head-out immersion in humans

1989 ◽  
Vol 257 (3) ◽  
pp. F375-F382 ◽  
Author(s):  
T. J. Rabelink ◽  
H. A. Koomans ◽  
P. Boer ◽  
C. A. Gaillard ◽  
E. J. Dorhout Mees
Keyword(s):  
Renal Plasma Flow ◽  
Water Immersion ◽  
Free Water ◽  
Urine Osmolality ◽  
Sodium Absorption ◽  
Free Water Clearance ◽  
Target Segment ◽  
Small Rise ◽  
Natriuretic Effect

Atrial natriuretic peptide (ANP) may play a role in the natriuresis after acute circulatory challenges. To assess this role in head-out water immersion (HOI), we compared in clearance studies the effect of 3 h HOI with an equally natriuretic 3-h infusion of ANP [0.01 microgram.kg-1.min-1 human ANP-(99-126)] in seven healthy individuals taking a 100 mmol sodium diet. The studies were repeated after treatment with enalapril (20 mg twice daily), which in previous studies inhibited the natriuresis after ANP. HOI caused a natriuresis equal to that of ANP infusion despite an about five times smaller rise in plasma ANP. HOI increased and ANP decreased estimated renal plasma flow (ERPF). HOI increased maximal free water clearance and decreased fractional lithium reabsorption. ANP did not affect these variables but raised minimal urine osmolality. Enalapril enhanced the fall in ERPF caused by ANP and abolished its natriuretic effect; enalapril did not impair either the natriuresis after HOI or the increase in ERPF and the fall in lithium reabsorption. These data indicate that the low dosage of ANP causes natriuresis by reducing sodium absorption in a distal nephron target segment; enalapril impairs this effect, perhaps by enhancing ANP-induced vasoconstriction, which decreases delivery to this target segment. HOI, by increasing sodium delivery to this segment, is natriuretic despite only a small rise in plasma ANP. Enalapril does not impair these effects. Although a rise in plasma ANP may be one factor in the natriuresis of HOI, the present data speak against an exclusive role. Other factors determine the magnitude of the natriuretic response.

Effect of sodium fluoride on concentrating and diluting ability in the rat

1977 ◽  
Vol 232 (4) ◽  
pp. F335-F340 ◽  
Author(s):  
J. D. Wallin ◽  
R. A. Kaplan
Keyword(s):  
Cyclic Amp ◽  
Urine Volume ◽  
Free Water ◽  
Urine Osmolality ◽  
Inhibitory Effect ◽  
Sprague Dawley ◽  
Free Water Clearance ◽  
Sprague Dawley Rats ◽  
Direct Inhibitory Effect ◽  
Hereditary Hypothalamic Diabetes Insipidus

Mechanisms for the concentrating defect produced by fluoride were examined in the rat. Free-water clearance at all levels of delivery was normal after 5 days of chronic fluoride administration in the hereditary hypothalamic diabetes insipidus rat. In the Sprague-Dawley rats, during moderate fluoride administration (120 micronmol/kg per day), urine osmolality and cyclic AMP excretion decreased and urine volume increased, but after exogenous vasopressin, volume decreased and osmolality and cyclic AMP increased appropriately. During larger daily doses of fluoride (240 micronmol/kg per day) urinary osmolality and cyclic AMP decreased and volume increased, which was similar to the changes seen during lower fluoride dosages, but these parameters did not change after exogenous vasopressin. These data suggest that ascending limb chloride reabsorption is unaltered by fluoride administration; in the presence of sufficient fluoride, collecting tubular cells apparently do not generate cyclic AMP or increase permeability appropriately in response to vasopressin. The postulated defect is felt to be due to either a decrease in ATP availability or to a direct inhibitory effect of fluoride on the vasopressin-dependent cyclic AMP generating system.

Osmoregulation of thirst and vasopressin during normal menstrual cycle

1988 ◽  
Vol 254 (4) ◽  
pp. R641-R647 ◽  
Author(s):  
T. J. Vokes ◽  
N. M. Weiss ◽  
J. Schreiber ◽  
M. B. Gaskill ◽  
G. L. Robertson
Keyword(s):  
Menstrual Cycle ◽  
Luteal Phase ◽  
Plasma Osmolality ◽  
Free Water ◽  
Urine Osmolality ◽  
Free Water Clearance ◽  
Vasopressin Release ◽  
Plasma Vasopressin ◽  
Normal Menstrual Cycle ◽  
Basal Plasma

Changes in osmoregulation during normal menstrual cycle were examined in 15 healthy women. In 10 women, studied repetitively during two consecutive menstrual cycles, basal plasma osmolality, sodium, and urea decreased by 4 mosmol/kg, 2 meq/l, and 0.5 mM, respectively (all P less than 0.02) from the follicular to luteal phase. Plasma vasopressin, protein, hematocrit, mean arterial pressure, and body weight did not change. In five other women, diluting capacity and osmotic control of thirst and vasopressin release were assessed in follicular, ovulatory, and luteal phases. Responses of thirst and/or plasma vasopressin, urine osmolality, osmolal and free water clearance to water loading, and infusion of hypertonic saline were normal and similar in the three phases. However, the plasma osmolality at which plasma vasopressin and urine osmolality were maximally suppressed as well as calculated osmotic thresholds for thirst and vasopressin release were lower by 5 mosmol/kg in the luteal than in the follicular phase. This lowering of osmotic thresholds for thirst and vasopressin release, which occurs in the luteal phase, is qualitatively similar to that observed in pregnancy and should be taken into account when studying water balance and regulation of vasopressin secretion in healthy cycling women.

Cardiovascular, renal, and endocrine responses to intravenous endothelin in conscious dogs

1988 ◽  
Vol 255 (6) ◽  
pp. R1064-R1068 ◽  
Author(s):  
K. L. Goetz ◽  
B. C. Wang ◽  
J. B. Madwed ◽  
J. L. Zhu ◽  
R. J. Leadley
Keyword(s):  
Vascular Endothelial Cells ◽  
Peripheral Resistance ◽  
Free Water ◽  
Urine Osmolality ◽  
Urinary Sodium Excretion ◽  
Conscious Dogs ◽  
Plasma Norepinephrine ◽  
Vascular Endothelial ◽  
Free Water Clearance ◽  
Physiological Processes

Endothelin is a recently discovered vasoconstrictor peptide that is synthesized in certain vascular endothelial cells. We have identified the cardiovascular, renal, and hormonal responses that can be elicited in conscious dogs by intravenous administration of endothelin at rates of 10 and 30 ng.kg-1.min-1 for 60 min (0.24 and 0.72 nmol.kg-1/1-h infusion). Each dose of endothelin increased total peripheral resistance, arterial pressure, and left atrial pressure and decreased heart rate and cardiac output. Hematocrit increased by 4.8% (NS) and 22.9% (P less than 0.01) in response to the lower and higher infusion rates, respectively. Urinary sodium excretion, urine osmolality, and osmolar clearance decreased and free water clearance increased. The lower dose of endothelin decreased plasma norepinephrine and increased plasma atriopeptin. The higher dose increased plasma levels of vasopressin, renin, aldosterone, norepinephrine, epinephrine, and atriopeptin. The higher infusion rate of the peptide caused one or more brief vomiting episodes in four of five dogs. Although it is not yet known whether endothelin is a circulating hormone, it is clear that this peptide is capable of causing profound cardiovascular, renal, and endocrine alterations in conscious dogs. The possible relevance of these observations to physiological processes and to pathological conditions such as hypertension remains to be established.

Contralateral renal function after unilateral renal vein ligation

1959 ◽  
Vol 197 (5) ◽  
pp. 1093-1096
Author(s):  
Joseph H. Perlmutt
Keyword(s):  
Renal Function ◽  
Renal Vein ◽  
Left Renal Vein ◽  
Free Water ◽  
Urine Osmolality ◽  
Tubular Reabsorption ◽  
Experimental Conditions ◽  
Free Water Clearance ◽  
Excretion Rates ◽  
The Right

The effect of increased pressure in one kidney, produced by ligation of its vein, on contralateral renal function was investigated in eight anesthetized dogs. Kidney function was determined under the same experimental conditions in five dogs, but without renal vein ligation. For the latter group, renal function, on the average, remained reasonably stable. After left renal vein ligation, findings for the right kidney were as follows: a) decreased urine flow, amounting maximally to 9.5–41.4% of control flows; b) slight increase of questionable significance in creatinine clearance; c) inconstant changes in PAH clearance; d) increase in urine osmolality to hypertonic values; e) decrease in solute-free water clearance; f) slight rise of questionable significance in total solute clearance; and g) either no change or inconstant changes in excretion rates Na+ and K+. The data indicate that the oliguria resulted solely from increased renal tubular reabsorption of water, suggesting liberation of antidiuretic hormone as the possible mechanism. Direct nervous influences on tubular reabsorption of water cannot, however, be presently ruled out.

Sign in / Sign up

Export Citation Format

Share Document