Effect of high salt intake on sodium, potassium-dependent adenosine triphosphatase activity in the erythrocytes of normotensive men

1988 ◽  
Vol 75 (2) ◽  
pp. 167-170 ◽  
Author(s):  
Antonio P. Quintanilla ◽  
Maria I. Weffer ◽  
Haengil Koh ◽  
Mohammed Rahman ◽  
Agostino Molteni ◽  
...  

1. We measured ouabain-insensitive adenosine triphosphatase (ATPase), sodium, potassium-dependent adenosine triphosphatase (Na+,K+-ATPase) and intracellular Na+ and K+ in the erythrocytes of 19 healthy volunteers, before and after supplementation of their normal diet with 6.0–8.9 g of salt (102–137 mmol of NaCl) per day, for 5 days. 2. The subjects had a small but significant gain in weight. Mean plasma renin activity decreased from 1.57 to 0.73 pmol of angiotensin I h−1 ml−1 and plasma aldosterone from 0.46 to 0.24 nmol/l. 3. Total ATPase activity fell from 197.9 nmol of inorganic phosphate h−1 mg−1 during the control period to 173.5 during the high-salt period (P < 0.0125). Na+,K+-ATPase activity fell from 162.2 to 141.4 nmol of inorganic phosphate h−1 mg−1 (P < 0.05). Intracellular Na + and intracellular K+ did not change. 4. These results are consistent with the hypothesis that salt-induced volume expansion causes the release of a factor inhibitory to the Na+ pump.

1990 ◽  
Vol 259 (6) ◽  
pp. H1629-H1636 ◽  
Author(s):  
J. E. Krieger ◽  
J. F. Liard ◽  
A. W. Cowley

The sequential hemodynamics, fluid and electrolyte balances, and the hormonal responses to a 7-day high-salt (NaCl) intake were investigated in sodium-depleted conscious dogs (n = 6). Studies were carried out in metabolic cages mounted on sensitive load cells, which enabled continuous 24 h/day monitoring of total body weight (TBW) as an index of changes in body water. Beat-by-beat hemodynamics were determined 24 h/day. Water (700 ml/day iv) intake was maintained constant. Daily fluid and electrolyte balances and hormonal analyses were performed. An increase of daily salt intake from 8 to 120 meq increased TBW 251 +/- 44 g (P less than 0.05), which was sustained thereafter. Average 24-h mean arterial pressure (MAP) and heart rate (HR) remained unchanged. Average cardiac output (CO) increased 11% (P less than 0.05) above control values by day 2, while total peripheral resistance (TPR) decreased proportionally. CO and TPR returned to control values only when low salt was resumed. Blood volume (BV) was unchanged on day 2 as indicated by direct measurement of BV (51Cr-labeled red blood cells) or by analysis of plasma protein concentration. A 92-meq (P less than 0.05) sodium retention was observed initially, and plasma sodium concentration increased slightly. Plasma renin activity, angiotensin II, and aldosterone levels decreased significantly, whereas vasopressin and atrial natriuretic peptide levels remained unchanged. In summary, chronic high-salt intake resulted in a net retention of water and sodium with no changes in MAP, HR, or BV. The rise in CO was offset by a reduction in TPR, which appeared at least in part related to angiotensin II suppression.


2012 ◽  
Vol 303 (1) ◽  
pp. F130-F138 ◽  
Author(s):  
Yanjie Huang ◽  
Tatsuo Yamamoto ◽  
Taro Misaki ◽  
Hiroyuki Suzuki ◽  
Akashi Togawa ◽  
...  

Despite suppression of the circulating renin-angiotensin system (RAS), high salt intake (HSI) aggravates kidney injury in chronic kidney disease. To elucidate the effect of HSI on intrarenal RAS, we investigated the levels of intrarenal prorenin, renin, (pro)renin receptor (PRR), receptor-mediated prorenin activation, and ANG II in chronic anti-thymocyte serum (ATS) nephritic rats on HSI. Kidney fibrosis grew more severe in the nephritic rats on HSI than normal salt intake. Despite suppression of plasma renin and ANG II, marked increases in tubular prorenin and renin proteins without concomitant rises in renin mRNA, non-proteolytically activated prorenin, and ANG II were noted in the nephritic rats on HSI. Redistribution of PRR from the cytoplasm to the apical membrane, along with elevated non-proteolytically activated prorenin and ANG II, was observed in the collecting ducts and connecting tubules in the nephritic rats on HSI. Olmesartan decreased cortical prorenin, non-proteolytically activated prorenin and ANG II, and apical membranous PRR in the collecting ducts and connecting tubules, and attenuated the renal lesions. Cell surface trafficking of PRR was enhanced by ANG II and was suppressed by olmesartan in Madin-Darby canine kidney cells. These data suggest the involvement of the ANG II-dependent increase in apical membrane PRR in the augmentation of intrarenal binding of prorenin and renin, followed by nonproteolytic activation of prorenin, enhancement of renin catalytic activity, ANG II generation, and progression of kidney fibrosis in the nephritic rat kidneys on HSI. The origin of the increased tubular prorenin and renin remains to be clarified. Further studies measuring the urinary prorenin and renin are needed.


2006 ◽  
Vol 290 (3) ◽  
pp. R553-R559 ◽  
Author(s):  
Paolo Manunta ◽  
Bruce P. Hamilton ◽  
John M. Hamlyn

High-salt diets elevate circulating Na+ pump inhibitors, vascular resistance, and blood pressure. Ouabain induces a form of hypertension mediated via the α2-Na+ pump isoform and the calcium influx mode of the vascular sodium calcium exchanger (NCX). Whereas elevated levels of an endogenous ouabain (EO) and NCX have been implicated in salt-sensitive hypertension, acute changes in sodium balance do not affect plasma EO. This study investigated the impact of longer-term alterations in sodium balance on the circulating levels and renal clearance of EO in normal humans. Thirteen normal men consumed a normal diet, high-salt diet, and hydrochlorothiazide (HCTZ), each for 5-day periods to alter sodium balance. EO and other humoral and urinary variables were determined daily. On a normal diet, urinary sodium excretion (140 ± 16 meq/day), plasma EO (0.43 ± 0.08 nmol/l) and urinary EO excretion (1.04 ± 0.13 nmol/day) were at steady state. On the 3rd day of a high-salt diet, urine sodium excretion (315 ± 28 meq/day), plasma EO (5.8 ± 2.2 nmol/l), and the urinary EO excretion (1.69 ± 0.27 nmol/day) were significantly increased, while plasma renin activity and aldosterone levels were suppressed. The salt-evoked increase in plasma EO was greater in older individuals, in subjects whose baseline circulating EO was higher, and in those with low renal clearance. During HCTZ, body weight decreased and plasma renin activity, aldosterone, and EO (1.71 ± 0.77 nmol/l) rose, while urinary EO excretion remained within the normal range (1.44 ± 0.31 nmol/day). Blood pressure fell in one subject during HCTZ. HPLC of the plasma extracts showed one primary peak of EO immunoreactivity with a retention time equivalent to ouabain. High-salt diets and HCTZ raise plasma EO by stimulating EO secretion, and a J-shaped curve relates sodium balance and EO in healthy men. Under normal dietary conditions, ∼98% of the filtered load of EO is reabsorbed by the kidney, and differences in the circulating levels of EO are strongly influenced by secretion and urinary excretion of EO. The dramatic impact of high-salt diets on plasma EO is consistent with its proposed role as a humoral vasoconstrictor that links salt intake with vascular function in hypertension.


1972 ◽  
Vol 55 (2) ◽  
pp. 369-376 ◽  
Author(s):  
P. G. BURSTYN ◽  
D. F. HORROBIN ◽  
M. S. MANKU

SUMMARY The effects of aldosterone on sodium, potassium and water excretion during various treatment regimes were studied in six Merino ewes. Urine was collected from 12.00 to 14.00 h and from 14.00 to 16.00 h each day. Intravenous injections of either 1 ml isotonic saline or 500 μg aldosterone were given at 13.30 h and excretion during the second collection period compared with that in the first. When each animal was given a salt (NaCl) supplement of 80 mequiv./day by i.v. injection, aldosterone caused marked sodium retention with no effect on potassium. When salt supplements of 400 mequiv./day were given, aldosterone lost its sodium-retaining action in all animals and caused a marked saluresis with a small increase in potassium excretion in five sheep out of six. Injections of sheep pituitary prolactin or of oxytocin restored the sodium-retaining action of aldosterone in spite of a continued high salt intake. The animals gained very little weight when treated with 400 mequiv. salt alone but did gain significantly when treated with salt plus prolactin. The weight gain was rapidly lost when the prolactin and high salt intake were discontinued.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Yulia Grigorova ◽  
Wen Wei ◽  
Valentina Zernetkina ◽  
Ondrej Juhasz ◽  
Edward Lakatta ◽  
...  

Background: Marinobufagenin (MBG), an endogenous cardiotonic steroid, is a Na/K-ATPase inhibitor and a vasoconstrictor. Previously it was demonstrated, that administration of 3E9 anti-MBG-antibody (mAb) reduced blood pressure (BP) and reversed left ventricular fibrosis in animal models of salt-sensitive hypertension and nephropathy. In the present study we investigated whether mAb alleviates BP and vascular remodeling in normotensive rats on a high salt intake. Methods: Wistar rats (5 months old) received normal salt diet (CTRL; n=8) or high salt intake (2% NaCl in drinking water) for 4 weeks. Rats on a high salt were administered vehicle (SALT; n=8) or mAb (50 ug/kg) (SALT-AB; n=8) 3 times during the last week of a high salt diet. BP was measured at baseline, after 3 and 4 weeks of experiment. Na/K-ATPase activity was measured in erythrocytes. Aortas were weighed, and were used to study sensitivity to the vasorelaxant effect of sodium nitroprusside (SNP), and for the histochemistry analysis of collagen deposition. Renal 24-hr MBG excretion was measured at week 4. Results: In SALT vs. CTRL, in the absence of BP changes, elevated levels of MBG (14.1±1.1 vs. 9.0±1.6 pmol/24hr, p<0.05) were associated with inhibition of erythrocyte Na/K-ATPase (12.6±0.3 vs. 14.2±0.35 μmol Pi/ml/hr, p<0.05), increased aortic weights (217±15 vs. 158±9 mg/kg BW, p<0.01), increased levels of collagen in aorta (2.5-fold; p<0.05), and compromised SNP vasorelaxant effect in aortic explants (EC50=167±19.3 nM vs. 99±2.0 nM; P<0.01). Antibody treatment in SALT-AB vs. SALT increased Na/K-ATPase activity (13.93±0.54 μmol Pi/ml/hr, p<0.05), reduced the aortic weight (180±12 mg/kg; P<0.05) and collagen deposition 3-fold (P<0.05), and restored the vasorelaxation of aortic rings by SNP to the levels in CTRL (70±1.5 nM, p<0.01). Conclusion: These findings for the first time demonstrated that in normotensive rats on a high salt intake heightened MBG levels induced vascular fibrosis and impairment of vasorelaxation in the absence of blood pressure changes. Immunoneutralization of MBG reversed these changes. Thus, high dietary NaCl intake in normotensive animals can stimulate vascular fibrosis via pressure-independent/ MBG-dependent mechanisms, and this remodeling is reversible.


1994 ◽  
Vol 16 (3) ◽  
pp. 327-340 ◽  
Author(s):  
Paul Wai Ching Li ◽  
C S Ho ◽  
R Swaminathan

1982 ◽  
Vol 19 (1) ◽  
pp. 38-45 ◽  
Author(s):  
J. R. Easley

Lithium chloride was given intraperitoneally to dogs at a dosage of 125 mg/kg body weight for three days. Kidneys were removed for morphologic examination and quantitation of sodium-potassium-adenosine triphosphatase (Na-K-ATPase) activity in cortical and medullary tissue. Light microscopy showed no changes in the kidneys, but cytoplasmic vacuolation and dilatation of the cisternae of the endoplasmic reticulum were seen ultrastructurally in the epithelial cells of the distal tubule and cortical and medullary collecting ducts. Mean cortical Na-K-ATPase activity was 1.49 ± 0.25 and 1.70 ± 0.31 μmoles inorganic phosphate/mg protein/hour in control and experimental groups respectively. Mean medullary Na-K-ATPase activity was 4.71 ± 0.41 and 5.01 ± 0.47 μmoles inorganic phosphate/mg protein/hour in control and experimental groups respectively. It was concluded that lithium produced morphologic changes in the distal nephron, but had no effect on renal Na-K-ATPase activity.


2012 ◽  
Vol 18 (8) ◽  
pp. 691-701 ◽  
Author(s):  
Xiu-Yang Li ◽  
Xian-Lei Cai ◽  
Ping-Da Bian ◽  
Liu-Ru Hu

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