Endogenous ANP augments fractional excretion of Pi, Ca, and Na in rats with reduced renal mass

1988 ◽  
Vol 255 (6) ◽  
pp. F1091-F1097 ◽  
Author(s):  
F. V. Ortola ◽  
B. J. Ballermann ◽  
B. M. Brenner
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Sodium Phosphate ◽  
Renal Mass ◽  
Sodium Intake ◽  
Fractional Excretion ◽  
Sodium Restriction ◽  
Calcium And Magnesium ◽  
Excretion Rates ◽  
Magnesium Excretion

Atrial natriuretic peptide (ANP) infusion increases fractional excretion of many solutes including sodium, chloride, bicarbonate, phosphate, calcium, and magnesium. Because fractional excretion of these solutes increases with advancing renal disease, and because plasma ANP levels are known to be elevated in chronic renal failure, we sought to determine whether ANP mediates increased solute excretion rates per nephron in rats following extensive renal ablation, a model of chronic renal failure. Because sodium restriction decreases plasma ANP levels in the setting of reduced renal mass, we also determined the effect of sodium restriction on sodium, phosphate, calcium, and magnesium excretion rates in rats with 5/6 nephrectomy (NX). We also assessed whether high endogenous ANP levels influence fractional sodium, phosphate, calcium, and magnesium excretion in rats with 5/6 NX, by inhibiting ANP action via infusion of a high-affinity ANP antiserum. Whole-kidney glomerular filtration rate in 5/6 NX rats averaged approximately one-third that of shams, and plasma ANP levels were significantly elevated in these rats above those of shams, but to a lesser extent in rats on low- vs. high-salt intakes. Fractional sodium, phosphate, and calcium, but not magnesium excretion rates were significantly greater in 5/6 NX rats on the higher sodium intake compared with those in 5/6 NX rats on the lower sodium intake. Moreover, in 5/6 NX rats on the higher sodium intake, ANP antiserum significantly reduced fractional sodium, phosphate, and calcium excretion, but was without effect on magnesium excretion. These data implicate endogenous ANP in promoting the adaptive increase in sodium, phosphate, calcium, but not magnesium excretion per nephron in chronic renal disease.

Atrial natriuretic factor and changes in dietary sodium intake in patients with chronic renal failure

1990 ◽  
Vol 78 (3) ◽  
pp. 327-334 ◽  
Author(s):  
J. C. Dussaule ◽  
C. Michel ◽  
J. P. Wolf ◽  
S. Czekalski ◽  
F. Mignon ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Plasma Renin Activity ◽  
Atrial Natriuretic Factor ◽  
Sodium Intake ◽  
Plasma Renin ◽  
Fractional Excretion ◽  
Renin Activity ◽  
Natriuretic Factor ◽  
Atrial Natriuretic

1. In order to examine the potential role of atrial natriuretic factor in modulating the increased sodium excretion per nephron in chronic renal failure, we studied 12 uraemic patients on the last day of two successive 7 day periods during which their sodium intake was 100 and 20 mmol of sodium/day, respectively. 2. There was a parallel decrease from 6.31 ± 0.75 to 2.17 ± 0.32% in the fractional excretion of filtered sodium and from 234.4 ± 74.9 to 80.6 ± 20.3 pg/ml (supine position) or 140.1 ± 43.6 to 60.7 ± 14.6 pg/ml (upright position) in plasma atrial natriuretic factor. Both parameters were significantly correlated during the two periods of different sodium intake (P <0.05). The ratio of plasma guanosine 3′:5′-cyclic monophosphate to plasma creatinine changed proportionally to plasma atrial natriuretic factor. Plasma aldosterone and plasma renin activity increased during the sodium-depleted period but only plasma renin activity was significantly correlated with fractional excretion of filtered sodium. 3. The predominant role of atrial natriuretic factor compared with that of aldosterone in the renal response to varying sodium intake is suggested both by regression analysis and by the effect of 5 day's treatment with a converting enzyme inhibitor (enalapril) in six other uraemic patients on a normal (100 mmol/day) sodium intake. Such treatment, although resulting in a significant increase in plasma renin activity and a significant decrease in plasma aldosterone, at least in the supine position, did not modify the fractional excretion of sodium and plasma atrial natriuretic factor. 4. Taken together, these results suggest a role for plasma atrial natriuretic factor in promoting the adaptation of sodium excretion on chronic changes of sodium intake in patients with chronic renal failure.

Effect of Proportional Reduction of Sodium Intake on the Adaptive Increase in Glomerular Filtration Rate/Nephron and Potassium and Phosphate Excretion in Chronic Renal Failure in the Rat

1975 ◽  
Vol 49 (3) ◽  
pp. 193-200 ◽  
Author(s):  
C. H. Espinel
Keyword(s):  
Renal Failure ◽  
Glomerular Filtration Rate ◽  
Chronic Renal Failure ◽  
Glomerular Filtration ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Sodium Intake ◽  
Dietary Sodium ◽  
Control Group ◽  
Phosphate Excretion

1. The influence of dietary sodium intake on the glomerular filtration rate (GFR/nephron) and potassium and phosphate excretion was examined at three stages of progressive chronic renal failure produced in rats by sequential partial nephrectomies. 2. The adaptive increased sodium excretion per nephron in the control group receiving a constant sodium intake did not occur in the experimental group that had a gradual reduction of dietary sodium in direct proportion to the fall in GFR. 3. Despite the difference in sodium excretion, the increase in GFR/nephron, the daily variation in the amount of potassium and phosphate excreted, the increase in potassium and phosphate excretion per unit nephron, and the plasma potassium and phosphate concentrations were the same in the two groups. 4. The concept of ‘autonomous adaptation’ in chronic renal failure is presented.

Inhibition of neutral endopeptidase stimulates renal sodium excretion in patients with chronic renal failure

1993 ◽  
Vol 84 (1) ◽  
pp. 31-39 ◽  
Author(s):  
J. C. Dussaule ◽  
C. Michel ◽  
M. N. Peraldi ◽  
J. M. Lecomte ◽  
C. Gros ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Cyclic Gmp ◽  
Atrial Natriuretic Factor ◽  
Fractional Excretion ◽  
Neutral Endopeptidase ◽  
Factor Level ◽  
Natriuretic Factor ◽  
Fractional Excretion Of Sodium ◽  
Atrial Natriuretic

1. The acute effects of a single oral dose of sinorphan (100 mg), an inhibitor of neutral endopeptidase, on the plasma atrial natriuretic factor level and the fractional excretion of sodium were examined in 12 patients with severe chronic renal failure who were not on maintenance haemodialysis and who ingested a normal sodium diet. The drug was administered against placebo by a double-blind cross-over protocol. 2. Basal plasma atrial natriuretic factor level and fractional excretion of sodium were high (23.2 ± 3.7 pmol/l and 2.64 ± 0.38%, respectively). Sinorphan inhibited plasma neutral endopeptidase activity by 68–75% 30 min after ingestion. This effect persisted for at least 4 h. There were simultaneously increases in plasma atrial natriuretic factor and cyclic GMP levels to 1.9 and 1.4 times the basal values, respectively. Fractional excretion of sodium increased during the second and third hour periods after ingestion of the drug with a peak of 1.9 times the basal value in the second period. Changes in fractional excretion of sodium were significantly correlated with those in plasma atrial natriuretic factor and cyclic GMP levels. Plasma aldosterone level, creatinine clearance and mean blood pressure were unchanged, whereas plasma renin activity increased slightly. An increase in urinary cyclic GMP excretion was observed in parallel with the increase in plasma cyclic GMP level. 3. The results of the present study indicate that (i) high basal values of plasma atrial natriuretic factor level and fractional excretion of sodium, as observed in patients with chronic renal failure, are associated with marked effects of neutral endopeptidase inhibition; (ii) fractional sodium excretion increases after protection of endogenous atrial natriuretic factor from degradation independently of any initial change in extracellular fluid volume or sodium intake, which suggests that this hormone may play a role in the control of sodium excretion in chronic renal failure.

scholarly journals Early effects of contrast media on renal hemodynamics and tubular function in chronic renal failure.

1995 ◽  
Vol 6 (5) ◽  
pp. 1451-1458
Author(s):  
D Russo ◽  
R Minutolo ◽  
B Cianciaruso ◽  
B Memoli ◽  
G Conte ◽  
...  
Keyword(s):  
Renal Failure ◽  
Single Dose ◽  
Chronic Renal Failure ◽  
Contrast Media ◽  
Fractional Excretion ◽  
Sodium Concentration ◽  
Renal Hemodynamics ◽  
Fractional Excretion Of Sodium ◽  
Urinary Levels ◽  
Renal Hypoperfusion

The pathophysiology and prevention of contrast media (CM)-induced nephropathy in chronic renal failure (CRF) are still ill defined. GFR, RPF, endothelin-1 (ET-1) levels, urinary sodium concentration, and fractional excretion of sodium were measured in CRF patients undergoing water diuresis in basal conditions and 20 to 120 min after an iv bolus of either the high-osmolar CM diatrizoate (D) or the low-osmolar CM iopamidol (I). The two CM induced an immediate and progressive decline of both GFR and RPF in the absence of hypovolemia, more pronounced in D (-36% at 120 min) than after I (-19% at 120 min; P < 0.05 versus D). Both CM determined a marked and steady increase of the fractional excretion of sodium. The natriuresis could not be totally ascribed to a CM-induced osmotic diuresis as because the urinary sodium concentration markedly increased. In two further groups of patients receiving D, we studied the effects of pretreatment with a single dose of either captopril or nifedipine. Both drugs, although not preventing the increase of natriuresis, partially antagonized D-induced renal hypoperfusion: GFR and RPF were equally reduced by 20% in D/captopril and D/nifedipine (P < 0.05 versus D). In unpretreated patients receiving either D or I, plasma ET-1 did not change but urinary levels increased; these changes were, however, dissociated from those observed in renal hemodynamics. Both plasma and urinary levels of ET-1 did not vary in pretreated groups. The 72-h follow-up evidenced a significant reduction of renal function only in the unpretreated D group. Therefore, the main findings after CM administration in CRF patients are: (1) an immediate GFR decline proportional to the osmolarity of CM and secondary to the renal hypoperfusion that is neither caused by hypovolemia nor mediated by ET-1, (2) an early tubular dysfunction at the level of the proximal nephron, and (3) a protective effect of single-dose pretreatment with either captopril or nifedipine on D-induced acute and short-term GFR changes.

Severe Renal Osteodystrophy Without Elevated Serum Immunoreactive Parathyroid Hormone Concentrations in Hypomagnesemia Due to Renal Magnesium Wasting

PEDIATRICS ◽  
1987 ◽  
Vol 79 (3) ◽  
pp. 403-409
Author(s):  
Israel Zelikovic ◽  
Shermine Dabbagh ◽  
Aaron L. Friedman ◽  
Mark L. Goelzer ◽  
Russell W. Chesney
Keyword(s):  
Renal Failure ◽  
Parathyroid Hormone ◽  
Elevated Serum ◽  
Fractional Excretion ◽  
Calcium Deficiency ◽  
Deficiency Rickets ◽  
Renal Magnesium Wasting ◽  
Magnesium Excretion ◽  
Moderate Renal Failure ◽  
Immunoreactive Parathyroid Hormone

An 8½-year-old girl presented with a long history of seizures, growth retardation, muscle weakness, gait disturbance, and hearing loss. Her evaluation revealed chronic moderate renal failure (serum creatinine 2.2 mg/dL), severe hypocalcemia (5 mg/dL), hyperphosphatemia (8.1 mg/dL), hypomagnesemia (1.5 mg/dL), increased urinary magnesium excretion (2 mg/kg/d), high fractional excretion of magnesium (21.7%), hypokalemia (3.2 mEq/L), and hyperkaliuria (26 mEq/L). Low circulating immunoreactive parathyroid hormone levels for the degree of the hypocalcemia (serum N-parathyroid hormone 212 pg/mL) and severe rickets without evidence of osteitis fibrosa cystica were found. The patient probably has primary renal leak hypomagnesemia (magnesuric hypomagnesemia) which caused impaired secretion of immunoreactive parathyroid hormone leading to severe hypocalcemia and calcium deficiency rickets. Treatment with magnesium and calcium supplements, calcitriol, and aluminum hydroxide resulted in marked clinical, biochemical, and radiologic improvement. Calcium deficiency rickets due to primary or secondary renal magnesium wasting in conjunction with moderate renal failure represents a largely unrecognized metabolic bone disease.

Acute effect of calcitonin on rat renal electrolyte transport

1981 ◽  
Vol 240 (1) ◽  
pp. F12-F16 ◽  
Author(s):  
S. Carney ◽  
L. Thompson
Keyword(s):  
Physiological Role ◽  
Fractional Excretion ◽  
Fold Increase ◽  
Plasma Calcium ◽  
Electrolyte Transport ◽  
Calcium Excretion ◽  
Phosphate Excretion ◽  
Renal Electrolyte Transport ◽  
Calcium And Magnesium ◽  
Magnesium Excretion

Renal clearance studies were performed on parathyroid-intact and acutely thyroparathyroidectomized (TPTX) rats to clarify calcitonin (CT) action on renal electrolyte transport. Although CT (0.15 U x 100 g body wt-1 x h-1) reduced fractional excretion of calcium and magnesium by 72 and 46%, respectively, in TPTX rats without altering sodium and phosphate excretion, a 10-fold increase in CT (1.5 U) caused a smaller reduction in calcium and magnesium excretion and significantly increased sodium and phosphate excretion. A higher CT dose (15 U) did not alter calcium excretion, increased magnesium excretion, and caused an even greater increase in sodium and phosphate excretion. Results in parathyroid-intact animals were similar. Despite the fall in plasma calcium following CT administration, the filtered calcium load was unaltered due to a concomitant increase in glomerular filtration rate. Calcium infusion prior to CT (0.15 U) prevented a detectable fall in plasma calcium concentration. However, a 45% fall in fractional calcium excretion occurred despite the significant increase in filtered calcium. These data suggest that the physiological role of calcitonin on the nephron is to conserve calcium. Reports of increased electrolyte excretion presumably reflect a depressant effect of pharmacological doses of CT on nephron function.

The Relative Importance of Urinary pH and Urinary Content of Citrate, Magnesium and Calcium in the Production of Nephro Calcinosis by Diet and Acetazolamide in the Rat

1970 ◽  
Vol 39 (5) ◽  
pp. 605-623 ◽  
Author(s):  
A. Z. Györy ◽  
K. D. G. Edwards ◽  
J. Robinson ◽  
A. A. Palmer
Keyword(s):  
Calcium Chloride ◽  
Urinary Calcium ◽  
Analysis Of Covariance ◽  
Calcium Excretion ◽  
Urinary Ph ◽  
Experimental Nephrocalcinosis ◽  
Calcium And Magnesium ◽  
Excretion Rates ◽  
Magnesium Excretion ◽  
Urinary Citrate

1. The association of varying levels of urinary pH, urinary citrate and urinary calcium and magnesium excretion rates with kidney citrate, calcium and magnesium concentrations in experimental nephrocalcinosis was examined in twenty-four rats in a 3 × 2 multifactorial experiment with four replicates. All rats received the same synthetic diet for 6 weeks before being killed in the seventh week. In addition the rats received calcium supplements as calcium chloride (diet A), calcium carbonate (diet B), or as an equal mixture of calcium chloride and carbonate (diet N), the content of calcium being kept constant at 6·3 mg per g of diet for all rats. Half of the rats also received 2·5 mg of acetazolamide per g of diet. 2. Diet A produced a systemic acidosis and the most acid urinary pH. Diet B plus acetazolamide produced a more severe systemic acidosis and the most alkaline urinary pH. Urinary magnesium, citrate and calcium excretion rates were generally reduced below normal. Urinary excretion of magnesium and calcium were significantly higher in those rats on diet A than in those on diet B, while urinary citrate excretion was highest in the latter. Acetazolamide caused a further increase in urinary calcium excretion but a decrease in urinary magnesium and citrate excretions. 3. Acetazolamide significantly reduced plasma calcium but elevated plasma magnesium. The changes produced in plasma and urinary calcium and magnesium in the present study were consistent with an action through systemic acidosis for calcium and through urinary pH for magnesium, both being effected at a tubular site. 4. Variation in diet alone as well as acetazolamide administration were significantly associated with variation in the degree of nephrocalcinosis (P < 0·05 and P < 0·005 respectively). Acetazolamide increased nephrocalcinosis by a factor of at least 10. Analysis of covariance showed that acetazolamide was no longer associated with significant nephrocalcinosis when its effects on urinary pH and magnesium were removed from its effect on nephrocalcinosis. Removal of the effect of acetazolamide on urinary citrate excretion did not alter the effect of acetazolamide in producing nephrocalcinosis. Although urinary citrate was reduced to below 10% of normal whenever nephrocalcinosis was severe, it was also reduced to below 10% in rats on diet A which had normal kidney tissue calcium content, the most acid urinary pH and the highest urinary magnesium. 5. Elevation of urinary pH and reduction in urinary magnesium excretion were therefore considered to be of major importance in the causation of experimental nephrocalcinosis; reduction in urinary citrate excretion appeared to be only of secondary importance.

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