Effect of NaCl infusion on urinary Ca++ and Mg++ during reduction in their filtered loads

Sg, Massry; Jw, Coburn; Chapman, LW

doi:10.1152/ajplegacy.1967.213.5.1218

Cited by 112 publications

(50 citation statements)

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“…It is possible that the need for Imlagiuemii by newvlv forimied bonle in the PD growing ralts, wvhich are in negative mlaginesiuinm balance, coIntributes to the magnitude of the hypomagnesemia. (15)(16)(17)(18). In our animals, magnesiuria developed in the absence of changes in urinary sodium excretion.…”

Section: Discussionmentioning

confidence: 67%

Effect of Phosphate Depletion on Magnesium Homeostasis in Rats

Kreußer¹,

Kurokawa²,

Aznar³

et al. 1978

J. Clin. Invest.

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A B S T R A C T The effects of phosphate depletion on magniesiumni (NMg) homeostasis were evaluated in rats fed a diet containing 0.03% phosphorus for periods up to 8 wk. Plasma phosphorus fell signiificantly (P < 0.01) from 10.1+0.27 (SE) to 5.0±0.54 mgIl00 ml within 1 day and conitiniued to fall gradually to a level of 1.2±0.21 mg/100 ml by the end of the 8th wk. A signiificant (P < 0.01) increment in urinary Mg excretion (UMgV) from 46±2.7 to 126±24 ,ueq/24 h occurred during the 1st day of phosphate depletion; UMgV reached a peak of 300±+24 pieq/24 h by the 3rd day and remained high ranging between 150-300 ,ueq/24 h, thereafter. The magnittude of the magnesuria was related to the degree of hypophosphatemia and was not affected by lowering the calcium intake and reducing the hypercalciuria. The concentration of plasma Mg fell significantly (P < 0.01) from 1.2±0.02 to 0.79±0.10 meq/liter by the 1st day of the study and remained low throughout.Mg balance became negative during the 1st day of phosphate depletion and remained so during the entire study. This occurred despite a significant increment in the fraction of ingested Mg absorbed which becarmie evident by the 3rd wk of phosphate depletion. Mg contenit of muscle, kidney, and liver were not affected but bone Mg was reduced significantly. The change in bone Mg was not due to an overall reduction in bone mineral contenit because bone calcium content was not affected. Supplementation of large amounts of Mg (800-1,000 ,ueq/day) in the drinking water produced a normalization of serum Mg but did not bring about restoration of bone Mg despite a positive Mg balance. The disturbances in Mg metabolism were independent of the age or veight of the animals.Our results indicate that phosphate depletion is Dr. Kreusser is a Fellow of the Deutsche Forschungsgemeinschaft.Dr. Aznar is a Fellow of the Del Amo Foundation.

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Section: Discussionmentioning

confidence: 67%

Effect of Phosphate Depletion on Magnesium Homeostasis in Rats

Kreußer¹,

Kurokawa²,

Aznar³

et al. 1978

J. Clin. Invest.

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“…The renal tubular reabsorption of calcium is closely related to that of sodium (17,18,20,21), and it is likely that certain events promoting sodium transport in the nephron can also augment the reabsorption of calcium. Also, enhanced tubular reabsorption of calcium follows increased action of parathyroid hormone (22,23).…”

Section: Resultsmentioning

confidence: 99%

“…Glomerular filtration rate (GFR) was estimated from endogenous creatinine clearance. Creatinine, sodium, calcium, and phosphorus in plasma and urine, and total protein and water content of plasma were measured by methods previously reported from this laboratory (17,18). The concentration of diffusible calcium in serum was measured in ultrafiltrates of serum prepared anaerobically (19) from eight patients with hyperparathyroidism before and on the 4th day of therapy with thiazides.…”

Section: Methodsmentioning

confidence: 99%

Changes in Serum and Urinary Calcium during Treatment with Hydrochlorothiazide: Studies on Mechanisms

Brickman¹,

Massry²,

Coburn³

1972

J. Clin. Invest.

219

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A B S T R A C T Studies were undertaken in man to evaluate the roles of volume depletion and of the parathyroid glands in mediating the changes in serum and urinary calcium which follow the administration of hydrochlorothiazide, 100 mg twice daily, for 4 days. 42 studies were carried out in 16 normal subjects, 9 patients with hyperparathyroidism, and 7 vitamin D-treated subjects with hypoparathyroidism. In six studies in normal subjects, daily sodium losses during thiazide administration were quantitatively replaced, and in six other studies the effect of equivalent sodium losses produced by furosemide was evaluated.Although the magnitude of sodium losses was similar in three groups during therapy with thiazides, urinary calcium fell and urinary phosphorus increased significantly only in normal subjects and those with hyperparathyroidism; no change occurred in patients with hypoparathyroidism. With the replacement of the thiazide-induced sodium losses by NaCl in normals, urinary calcium did not change as urinary sodium increased 4-to 5-fold. Furosemide administration produced similar sodium losses while urinary calcium remained at or above control levels. After correction for changes in plasma protein concentration caused by thiazide-induced hemoconcentration, mean levels of serum calcium were significantly increased only in subjects with hyperparathyroidism and vitamin D-treated patients with hypoparathyroidism.

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“…Amiloride or extracellular volume in that volume contraction increases magnesium conservation and volume expansion decreases magnesium absorption (101,123). Changes of magnesium reabsorption within the proximal tubule are not markedly altered even though NaCl and water are significantly affected (124).…”

Section: Extracellular Fluid Volumementioning

confidence: 99%

Epithelial magnesium transport and regulation by the kidney

C²

2000

Front Biosci

102

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Magnesium is the fourth most abundant cation in the body and the second most common cation in the intracellular fluid. It is the kidney that provides the most sensitive control for magnesium balance. About a 80% of the total serum magnesium is ultrafilterable through the glomerular membrane. In all of the mammalian species studied to date, the proximal tubule of the adult animal reabsorbs only a small fraction, 10-15%, of the filtered magnesium. Unlike the adult proximal convoluted tubule that of young rats (aged 13-15 days) reabsorbs 50-60% of filtered magnesium along the proximal tubule together with sodium, calcium, and water. Micropuncture experiments, in every species studied to date, indicates that a large part (approximately 60%) of the filtered magnesium is reabsorbed in the loop of Henle. Magnesium reabsorption in the loop occurs within the cortical thick ascending limb (cTAL) by passive means driven by the transepithelial voltage through the paracellular pathway. Micropuncture experiments have clearly showed that the superficial distal tubule reabsorbs significant amounts of magnesium. Unlike the thick ascending limb of the loop of Henle, magnesium reabsorption in the distal tubule is transcellular and active in nature. Many hormones and nonhormonal factors influence renal magnesium reabsorption to variable extent in the cTAL and distal tubule. Moreover, nonhormonal factors may have important implications on hormonal controls of renal magnesium conservation. Dietary magnesium restriction leads to renal magnesium conservation with diminished urinary magnesium excretion. Adaptation of magnesium transport with dietary magnesium restriction occurs in both the cTAL and distal tubule. Elevation of plasma magnesium or calcium concentration inhibits magnesium and calcium reabsorption leading to hypermagnesiuria and hypercalciuria. The

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Effect of NaCl infusion on urinary Ca++ and Mg++ during reduction in their filtered loads

Cited by 112 publications

References 0 publications

Effect of Phosphate Depletion on Magnesium Homeostasis in Rats

Effect of Phosphate Depletion on Magnesium Homeostasis in Rats

Changes in Serum and Urinary Calcium during Treatment with Hydrochlorothiazide: Studies on Mechanisms

Epithelial magnesium transport and regulation by the kidney

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