Aldosterone effects on water and electrolyte metabolism

1984 ◽  
Vol 100 (1) ◽  
pp. 93-100 ◽  
Author(s):  
C. J. Kenyon ◽  
N. A. Saccoccio ◽  
D. J. Morris

ABSTRACT The effects of constant infusions of small doses of adrenal steroid hormones on sodium, potassium and water metabolism were studied in male adrenalectomized rats. An infusion of 1 μg aldosterone/day was sufficient to restore normal sodium and potassium balance in a group of rats fed an unsupplemented diet. Log doses of aldosterone (0·1–10 μg/day for 4 days) administered some days after adrenalectomy caused linear increases in the body weight of rats fed a sodium-supplemented diet (0·05 m-NaCl as drinking fluid) during 4 days of treatment. Increases in body weight correlated with renal sodium and water balance. When steroid treatment was started at the time of adrenalectomy, sodium balance was not significantly affected although rats treated with 1 μg aldosterone/day ate more, drank less saline, produced a smaller volume of urine of greater osmolarity and gained more weight than controls. A dose of 100 μg 18-hydroxy-deoxycorticosterone/day had no significant effects. Fluid intake and urine volume were not significantly affected by 1 mg corticosterone/day but food intake, water balance and weight gain were greater than controls. Rats treated with both aldosterone and corticosterone showed a decrease in free water clearance. Aldosterone and corticosterone, both singly and in combination, reduced plasma potassium levels. Plasma sodium levels were only increased when aldosterone was administered on its own. Long-term steroid infusions have revealed more about the physiology of aldosterone action than could acute measurements of renal function. In particular, they have indicated that dietary intake of electrolytes as well as excretion are affected, that mineralocorticoid actions are distinct from glucocorticoid actions and that there are transient effects of aldosterone on fluid regulation which are not sustained under steady-state conditions. J. Endocr. (1984) 100,93–100

1970 ◽  
Vol 48 (3) ◽  
pp. 479-482 ◽  
Author(s):  
Maryanne Robinson Hughes

The mean values for six adult puffins were hematocrit, 0.511 ± 0.007; plasma sodium, 160.7 ± 2.3, potassium, 3.1 ± 0.1, and chloride, 133.4 ± 1.9 meq/l.The cloacal fluid of one young laboratory-reared puffin was always hypotonic to the plasma in Na and Cl and never contained more than one-half the ingested Na, K, or Cl; contained less than 40% of the ingested water; and solid material was less than 10% of the total as determined by dry weight.In one salt load experiment (4.0 ml 1.0 N NaCl/3 92-gram adult) the salt glands proved very efficient, producing a secretion of 975 meq/l (maximum) Cl and eliminating 75% of the load in 20 min. The salt glands and kidneys are large, 0.1% and 1.8% of the body weight respectively.


1975 ◽  
Vol 228 (6) ◽  
pp. 1847-1855 ◽  
Author(s):  
J Mohring ◽  
B Mohring ◽  
H-J Naumann ◽  
A Philippi ◽  
E Homsy ◽  
...  

In male Sprague-Dawley rats, renal artery constriction in the presence of an inact contralateral kidney induced sodium retention (for 2-3 wk), moderate potassium loss,elevation of blood volume (BV), and an increase in water turnover. It is suggestedthat renal artery constriction activates the renin-angiotensin-aldosterone system, resulting in disordered regulation of salt and water balance and in blood pressure (BP) elevation. Subsequently, sodium balance was reestablished in one group of hypertensive rats. The previously retained sodium was kept in the body, and BV and reninactivity remained elevated. In a second group of animals, a malignant course of hypertension developed: BP surpassed a critical level of about 180 mmHg; sodium, potassium, and water were lost; BV declined; renin activity was further stimulated; and in the contralateral kidney malignant nephrosclerosis occurred. It is assumed that pressure diuresis and natriuresis induce a vicious circle: the increasing renin activity may maintain or further increase BP level, therby inducing further salt and water loss, etc.; high BP levels and high renin activities induce vascular damage and deterioration of renal function.


1977 ◽  
Vol 232 (4) ◽  
pp. F335-F340 ◽  
Author(s):  
J. D. Wallin ◽  
R. A. Kaplan

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.


1972 ◽  
Vol 50 (5) ◽  
pp. 611-617 ◽  
Author(s):  
E. L. Bradley ◽  
W. N. Holmes

The supraorbital nasal glands were removed from the duck (Anas platyrhynchos) 1 week before experimentation. When sham-operated birds were given hypertonic saline drinking water (282 mM NaCl, 6 mM KCl) for 70 h they maintained their body weights and remained in positive water balance. When the ducks lacking nasal glands were similarly treated they became severely dehydrated, lost body weight at the rate of 5.59 ± 1.1 g/h and showed significant increases in the plasma concentrations of Na+, Cl−, K+, and total osmotically active material. When the glandless birds were given hypertonic saline drinking water, the disparity between the measured plasma osmolality and the osmolality calculated on the basis of the Na+, Cl−, and K+ concentrations in plasma increased two-fold. No such change in disparity between the measured and calculated osmolalities of plasma in the sham-operated birds was observed. Forty-eight hours after their return to a diet containing fresh drinking water, the birds without nasal glands regained some of the body weight they had lost and the plasma electrolyte concentrations were restored towards normal. It is concluded that in the absence of nasal glands, the kidney alone is incapable of maintaining positive water balance in ducks fed hypertonic saline as their only source of drinking water.


1974 ◽  
Vol 83 (1) ◽  
pp. 151-160 ◽  
Author(s):  
A. C. Field ◽  
A. R. Sykes ◽  
R. G. Gunn

SUMMARYExcretion of D.M., N, Ca, P and Mg in faeces, and N, P and Mg in urine were measured at intervals over 12 months in breeding Scottish Blackface sheep grazing hill pastures. These values were used with data on reproductive performance and body compositional changes, to calculate the energy, nitrogen and mineral balances. The sheep were: 11 6½-year-old with sound mouths (SM), 16 6½-year-old with broken mouths (BM), 16 5½-year-old with all permanent incisors clipped to gum level (CM) and 16 2½-year-old (Y). An energy supplement was given at the end of gestation and during early lactation. All faeces were collected and creatinine was used as an internal marker to estimate urine volume.Faecal D.M. output ranged from 443 to 662 g/day, with highest values in November and lowest in May. Average values for the BM sheep were lower than those for the other groups but when output was expressed as a power function of body weight, the values for the Y sheep were 15% higher than those for the other groups. Faecal excretions of Ca and P in January and February were very low and the values for P were half the expected endogenous faecal loss.Urinary output ofN ranged from 6·0 g/day in February to 22·2 g/day in August and the corresponding urinary urea N: total N ratios were 0·24 and 0·69. Urinary Mg output was highest in late summer and early winter but urinary P showed no consistent trends.The estimated daily intakes of DOM (g) were 936 in November 1969, 599 in January, 414 in February, 1075 in May, 1150 in August and 946 in November 1970.The loss of energy from the body between mating (November) and mid-lactation (June) ranged from 9·5 to 16·8% of the total calculated ME requirements in the Y and BM sheep, respectively. Maintenance requirements averaged 204 kJ/kg body weight/day and the value for the Y sheep was 12% higher than the mean for the older sheep.Nitrogen and mineral balances were calculated for February, May, August and November. The sheep were protein-deficient in winter, not from a shortage of crude protein in the diet but because of its low digestibility (34%). Intakes of Ca and P in winter were low and a real possibility of a P deficiency exists. Estimates of the concentrations of N and of minerals in the herbage consumed by the sheep were made and compared with those obtained for cut herbage from the same pastures. It would appear that the sheep selected herbage of a higher protein content than that of the cut herbage. Herbage selection was greatest in November.


1988 ◽  
Vol 65 (1) ◽  
pp. 318-324 ◽  
Author(s):  
H. Nose ◽  
G. W. Mack ◽  
X. R. Shi ◽  
E. R. Nadel

To investigate the influence of [Na+] in sweat on the distribution of body water during dehydration, we studied 10 volunteer subjects who exercised (40% of maximal aerobic power) in the heat [36 degrees C, less than 30% relative humidity (rh)] for 90-110 min to produce a dehydration of 2.3% body wt (delta TW). After dehydration, the subjects rested for 1 h in a thermoneutral environment (28 degrees C, less than 30% rh), after which time the changes in the body fluid compartments were assessed. We measured plasma volume, plasma osmolality, and [Na+], [K+], and [Cl-] in plasma, together with sweat and urine volumes and their ionic concentrations before and after dehydration. The change in the extracellular fluid space (delta ECF) was estimated from chloride distribution and the change in the intracellular fluid space (delta ICF) was calculated by subtracting delta ECF from delta TW. The decrease in the ICF space was correlated with the increase in plasma osmolality (r = -0.74, P less than 0.02). The increase in plasma osmolality was a function of the loss of free water (delta FW), estimated from the equation delta FW = delta TW - (loss of osmotically active substance in sweat and urine)/(control plasma osmolality) (r = -0.79, P less than 0.01). Free water loss, which is analogous to "free water clearance" in renal function, showed a strongly inverse correlation with [Na+] in sweat (r = -0.97, P less than 0.001). Fluid movement out of the ICF space attenuated the decrease in the ECF space.(ABSTRACT TRUNCATED AT 250 WORDS)


1991 ◽  
Vol 69 (8) ◽  
pp. 1196-1203 ◽  
Author(s):  
Dorothea E. Blandford ◽  
Donald D. Smyth

Previous studies have demonstrated a diuretic effect of clonidine at low intrarenal infusion rates with a natriuretic effect being observed at high infusion rates (≥3 μg∙kg−1∙min−1). The natriuresis at high infusion rates may have been secondary to increased renal prostaglandin production. We therefore evaluated the effects of indomethacin (a cyclooxygenase inhibitor) on the response to cionidine in the anesthetized rat. Intrarenal infusions of saline (vehicle) or clonidine (0.1, 0.3, 1, and 3 μg∙kg−1∙min−1) were examined both in the presence and absence of pretreatment with indomethacin (5 mg/kg, i.p.). Clonidine produced a dose-related increase in urine volume and free water clearance at 0.3, 1, and 3 μg∙kg−1∙min−1 as compared with the vehicle group. Sodium excretion and osmolar excretion were increased only at the highest infusion rate investigated. Following indomethacin pretreatment, clonidine produced a greater increase in urine volume at each infusion rate investigated. The indomethacin pretreatment also resulted in a potentiation of the natriuretic effect of clonidine at all infusion rates. Interestingly, this was associated with an increase in osmolar clearance but not free water clearance. These effects of indomethacin were reversed by infusion of prostaglandin E2. An infusion of prostaglandin E2 attenuated the indomethacin-induced increase in both urine flow rate and sodium excretion, indicating that the effects of indomethacin were mediated by prostaglandin inhibition. These results suggest that endogenous prostaglandin production attenuates the renal effects of clonidine, and as well, that in the presence of α2-adrenoceptor stimulation, prostaglandin E2 mediates an antidiuretic and antinatriuretic effect.Key words: clonidine, indomethacin, prostaglandin E2, diuresis, natriuresis.


1974 ◽  
Vol 61 (3) ◽  
pp. 487-500 ◽  
Author(s):  
I. W. HENDERSON ◽  
N. A. M. WALES

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'.


1982 ◽  
Vol 63 (6) ◽  
pp. 525-532 ◽  
Author(s):  
S. J. Walter ◽  
J. Skinner ◽  
J. F. Laycock ◽  
D. G. Shirley

1. The antidiuretic effect of hydrochlorothiazide in diabetes insipidus was investigated in rats with the hereditary hypothalamic form of the disease (Brattleboro rats). 2. Administration of hydrochlorothiazide in the food resulted in a marked fall in urine volume and a corresponding rise in osmolality. These effects persisted throughout the period of treatment (6–7 days). 3. Body weight and extracellular volume were significantly reduced in the thiazide-treated rats. 4. Hydrochlorothiazide caused an increase in urinary sodium excretion only on the first day of treatment. The resulting small negative sodium balance (in comparison with untreated rats) remained statistically significant for 2 days only. Thiazide-treated rats gradually developed a potassium deficit which was statistically significant from the fourth day of treatment. 5. Total exchangeable sodium, measured after 7 days of thiazide treatment, was not significantly different from that of untreated rats. However, plasma sodium was reduced in thiazide-treated animals, whereas erythrocyte sodium concentration was elevated. 6. It is concluded that the antidiuresis resulting from chronic hydrochlorothiazide administration is associated with a reduction in extracellular volume, but not with a significant overall sodium deficit. Hydrochlorothiazide appears to cause a redistribution of the body's sodium such that the amount of sodium in the extracellular fluid compartment is reduced.


1987 ◽  
Vol 252 (5) ◽  
pp. R833-R841 ◽  
Author(s):  
R. J. Roman ◽  
J. L. Osborn

Renal transplantation studies have indicated that some form of renal dysfunction underlies the development of hypertension in Dahl salt-sensitive (S) rats. In the present study, we compared renal hemodynamic and tubular function of conscious Dahl S and salt-resistant (R) rats. Prehypertensive Dahl S rats had a blunted natriuretic response to an intravenous isotonic sodium chloride load compared with the responses of normotensive Dahl R or hypertensive Dahl S rats. This difference was probably not related to a generalized defect in renal tubular handling of sodium and water, since prehypertensive Dahl S rats excreted quantities of sodium comparable to those of R or hypertensive S rats when infused with hypertonic sodium chloride solutions. Dahl S rats also elevated free water clearance and lowered urine osmolality similar to R rats when challenged with a hypotonic saline load. Renal blood flows and glomerular filtration rates were similar in prehypertensive Dahl S, hypertensive Dahl S, and Dahl R rats. The possible link between sodium retention and the development of hypertension in Dahl S rats was examined further by measuring the changes in sodium and water balance, extracellular fluid volume (ECV), and blood pressure after exposure to an 8% sodium chloride diet. No differences could be detected in the salt and water balances of Dahl S and R rats exposed to a high-salt diet for 14 days. ECV increased significantly by 10% in Dahl S rats on the 1st day of a high-salt diet, whereas no change was observed in Dahl R animals.(ABSTRACT TRUNCATED AT 250 WORDS)


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