Intraerythrocyte Magnesium Research Articles

Intra-erythrocytes magnesium deficiency could reflect cognitive impairment status due to vascular disease: a pilot study

Background and aimsMagnesium is a fundamental cation that regulates neuronal transmission, protein synthesis, energy metabolism. Magnesium deficiency mostly affects nervous and cardiovascular systems determining weakness, tremors, seizure and arrhythmias. This condition retains also a role in memory function and neuronal plasticity. Importantly magnesium deficiency could remain latent and asymptomatic resulting a risk factor for cardiovascular disease. In this sense we aim to determine magnesium status in patient presenting cognitive impairment of vascular origin.Methods21 healthy subjects and 27 patients presenting vascular cognitive impairment were included in this study. Both plasma and intraerythrocitary magnesium level were measured to detect magnesium deficiency and cognitive performance was evaluated trough Mini Mental State Evaluation (MMSE).ResultsHere we showed that patients presenting vascular cognitive impairment present intraerythrocitary magnesium level lower than age-matched healthy subjects. To note their plasma magnesium resulted within reference limit.ConclusionWe suggest that intracellular magnesium laboratory measurement is needed to detect occult magnesium deficiency in population at risk. Magnesium supplementation could represent an adjuvant for healthy aging in high risk population.

Comparison of two methods for the assessment of intra-erythrocyte magnesium and its determinants: Results from the LifeLines cohort study

BackgroundDirect methods for the assessment of intra-erythrocyte magnesium (dIEM) require extensive sample preparation, making them labor intensive. An alternative, less labor intensive method is indirect calculation of intra-erythrocyte magnesium (iIEM). We compared dIEM and iIEM and studied determinants of dIEM and iIEM, plasma magnesium and 24-h urinary magnesium excretion in a large population-based cohort study. MethodsdIEM and iIEM were measured using a validated inductively coupled plasma mass spectrometry (ICP-MS) method in 1669 individuals from the second screening from the LifeLines Cohort Study. We used linear regression analyses to study the determinants of IEM, plasma magnesium and 24-h urinary magnesium excretion. ResultsMean dIEM and iIEM were 0.20 ± 0.04 mmol/1012 cells and 0.25 ± 0.04 mmol/1012 cells, respectively. We found a strong correlation between dIEM and iIEM (r = 0.75). Passing-Bablok regression analyses showed an intercept of 0.015 (95% CI: 0.005; 0.023) and a slope of 1.157 (95% CI: 1.109; 1.210). In linear regression analyses, plasma levels of total- and LDL -cholesterol, and triglycerides were positively associated dIEM, iIEM, and plasma magnesium, while glucose and HbA1c were inversely associated with plasma magnesium. ConclusionsWe observed a strong correlation between dIEM and iIEM, suggesting that iIEM is a reliable alternative for the labor intensive dIEM method.

Total serum and intraerythrocyte magnesium concentrations in hemodialysis patients using different dialysate solutions.

Beside routinely used 0.5 mmol/L dialysate-magnesium, higher dialysate-magnesium (1.0 mmol/L) was recently introduced. The aim of this study was to evaluate the impact of different dialysate-magnesium on serum and intraerythrocyte levels of magnesium (Mg) before and after dialysis. The study included 43 patients receiving chronic hemodialysis, divided into two groups based on dialysate-magnesium (0.5 or 1.0 mmol/L) used prior to study initiation and during 12 months of follow-up. Blood samples were taken at the mid-week dialysis; total serum Mg was measured colorimetrically and intraerythrocyte Mg by atomic absorption spectrophotometry. Hypermagnesiemia-associated complications were observed for 12 months. Total serum Mg was 1.14 ± 0.19 mmol/L before and 0.95 ± 0.16 mmol/L after dialysis in patients using lower dialysate-Mg (p < 0.001), whereas it was 1.47 ± 0.25 mmol/L before and 1.49 ± 0.18 mmol/L after dialysis in patients using higher dialysate-Mg (p = 0.926). Intraerythrocyte Mg was 1.98 ± 0.34 mmol/L before and 1.97 ± 0.28 mmol/L after dialysis in the lower dialysate-Mg group (p = 0.939), while it was 2.09 ± 0.37 mmol/L before and 2.19 ± 0.48 mmol/L after dialysis in the higher dialysate group (p = 0.067). After 12 months total serum Mg decreased in both the groups, remaining lower in 0.5 mmol/L dialysate-Mg group. No hypermagnesiemia-related symptoms occur during 12 months of follow-up in both the groups. In patients using lower dialysate-Mg total serum Mg remains within the reference range and shows postdialytic decline, while in higher dialysate-Mg group it exceeded reference range before and after dialysis without significant intradialytic change. The intraerythrocyte values remain within reference range with both dialysates used. No clinical signs and symptoms of hypermagnesiemia occur during longer administration of higher dialysate-magnesium despite high total serum Mg level.

Роль желатиназы В и внутриэритроцитарного магния в механизмах хронизации воспаления эндометрия у крыс

Роль желатиназы В и внутриэритроцитарного магния в механизмах хронизации воспаления эндометрия у крыс

Intra-erythrocyte Magnesium Is Associated with Gamma-Glutamyl Transferase in Obese Children and Adolescents

This study aims at determining the association between markers of hepatic injury and serum, urinary, and intra-erythrocyte magnesium concentrations and dietary magnesium intake in obese children and adolescents. In a case-control study, 42 obese children and adolescents (8-18 years) and 42 sex- and puberty-matched controls were studied. Serum, urinary, and intra-erythrocyte magnesium levels, indices of insulin sensitivity, and liver enzymes were measured. Dietary magnesium intake was assessed using a food frequency questionnaire. Obese children and adolescents exhibited insulin resistance as determined by a higher fasting insulin and the HOMA-IR (p<0.001) and lower QUICKI indices (p=0.001); in addition these subjects had significantly higher intra-erythrocyte magnesium (IEM) concentrations, than non-obese ones (3.99±1.05 vs. 3.35±1.26 mg/dL of packed cell; p=0.015). Among liver enzymes, only gamma-glutamyl transferase (GGT) was significantly higher in obese than in non-obese subjects (22.7±9.4 vs. 17.1±7.9 U/l; p=0.002). A positive association was found between GGT and IEM in both groups; however in multivariate analysis, in obese subjects, only GGT (p=0.026) and, in non-obese subjects, only age (p=0.006) remained as significant predictors of IEM. In conclusion, increased IEM concentration was seen in insulin-resistant obese children and adolescents; furthermore, serum GGT was associated with IEM, independently of body mass index and HOMA-IR.

Influence of Therapy with Metformin on the Concentration of Certain Divalent Cations in Patients with Non-insulin-Dependent Diabetes Mellitus

Research was performed on a group of 30 patients with non-insulin-dependent diabetes mellitus (NIDDM), who never received antidiabetic medication before, and on a group of 17 healthy adults. The patients were administered treatment with metformin, 1,000 mg/day. Plasmatic and urinary concentration of magnesium have been measured, copper and zinc along with the concentrations of glucose, HDL, LDL, cholesterol, tryglicerides, HbA1c, and total erythrocyte magnesium, in advance and after 3 months of treatment. Data showed significant differences in the NIDDM group vs the control group: for plasma magnesium-1.95 ± 0.19 vs 2.20 ± 0.18 mg/dl, p < 0.001; urine magnesium-237.28 ± 34.51 vs 126.25 ± 38.22 mg/24 h, p < 0.001; erythrocyte magnesium-5.09 ± 0.63 vs 6.38 ± 0.75 mg/dl, p < 0.001; plasma zinc-67.56 ± 6.21 vs 98.41 ± 20.47 μg/dl, p < 0.001; urine zinc-1,347.54 ± 158.24 vs 851.65 ± 209.75 μg/24 h, p < 0.001; plasma copper-111.91 ± 20.98 vs 96.33 ± 8.56 μg/dl, p < 0.001; and urine copper-51.70 ± 23.79 vs 36.00 ± 11.70 μg/24 h, p < 0.05. Treatment with metformin for 3 months modified significant erythrocyte magnesium-5.75 ± 0.61 vs 5.09 ± 0.63 mg/dl, p < 0.001 and urine magnesium-198.27 ± 27.07 vs 237.28 ± 34.51 mg/24 h, p < 0.001, whereas it did not modify significant the plasmatic and urinary concentration of the other cations. The erythrocyte magnesium concentration was inversely correlated with HbA1c (r = -0.438, p = 0.015). The plasma level of copper was positively correlated with HbA1c (r = 0.517, p < 0.003), tryglicerides (r = 0.534, p < 0.003), and cholesterol (r = 0.440, p < 0.05), and the plasma level of zinc was inversely correlated with glycemia (r = -0.399, p = 0.029). Our data show a significant action of metformin therapy, by increasing the total intraerythrocyte magnesium concentration and decreasing the urinary magnesium elimination, positively correlated with the decrease of glycemia and HbA1c in NIDDM patients.

Magnesium metabolism after cardiac surgery in children.

OBJECTIVE: To analyze magnesium metabolism in children after cardiac surgery. DESIGN: Prospective observational study. SETTING: Pediatric intensive care unit (PICU) of a university hospital. PATIENTS: A total of 42 children in the perioperative period of cardiac surgery. MEASUREMENTS AND MAIN RESULTS: Determinations of serum magnesium (MgS), ultrafiltrable magnesium (MgU), intraerythrocytic magnesium, urinary magnesium, blood and urinary calcium, phosphorus, sodium, and blood and urinary creatinine were made in the operating room before surgery, at admission to the PICU, at 24 hrs, and at 3 and 5 days after surgery. The relationship with age, sex, diagnosis, type of surgery, arrhythmias, complications, length of stay in the PICU, and mortality was analyzed. MgS and MgU levels decreased after cardiac surgery (MgS before surgery, 0.74 +/- 0.09 mmol/L; MgS at admission to the PICU, 0.66 +/- 0.11 mmol/L; MgU before surgery, 0.56 +/- 0.06 mmol/L; MgU at admission to the PICU, 0.50 +/- 0.07 mmol/L; p <.0001 for both values). At admission to the PICU, 61.5% of the patients had MgS of <0.63 mmol/L, and 47.2% of the patients had an MgU of <0.46 mmol/L. MgS and MgU had increased by 24 hrs and showed further increases over the first 5 days after surgery. There were no significant changes in the intraerythrocytic magnesium levels in the postoperative period. Changes of MgS and MgU were greater after extracorporeal circulation than after closed surgery (p <.001). There was no correlation between MgS, MgU, or intraerythrocytic magnesium and other analytic and clinical parameters. No patient presented arrhythmias and none died. CONCLUSIONS: After cardiac surgery, and particularly after extracorporeal circulation surgery, children present with low MgS and MgU levels at admission to the PICU. MgS and MgU levels increase over the first 5 days after cardiac surgery. No relationship was found between magnesium levels and the postoperative course.

Magnesium, zinc and iron levels in pre-eclampsia.

To determine the change in erythrocyte and plasma magnesium, plasma zinc and serum iron concentrations in pre-eclampsia. Twenty women with pre-eclampsia and 20 control subjects matched for gestational age were examined. The levels of magnesium, zinc and iron in all subjects were measured by flame atomic absorption spectrometry. In the pre-eclamptic women, who were supplemented with magnesium salts, these measurements were repeated after delivery. The intraerythrocytic magnesium levels before supplementation were significantly lower in the pre-eclamptic patients than in the healthy pregnant women (0.98 +/- 0.15 vs. 1.35 +/- 0.30 mmol/l; p < 0.001) and increased (to 1.25 +/- 0.25 mmol/l) after treatment with magnesium. The plasma magnesium and zinc, and the serum iron concentrations were not significantly different between the pre-eclamptic and the healthy pregnant women. Our results suggest that low cellular magnesium levels in women with pre-eclampsia may contribute to the development of hypertension in these patients, and that the measurements of plasma zinc and serum iron concentrations are of doubtful clinical value in the management of pre-eclampsia.

Effects of magnesium on blood pressure and intracellular ion levels of Brazilian hypertensive patients

Fifteen patients with uncomplicated mild to moderate primary hypertension (7 males, 8 females, age range 36–65 years) were submitted to a double blind randomized crossover study, receiving MgO 3 times a day at a daily dose of 1.0 g (600 mg/day of magnesium) and placebo for a period of 6 weeks. This was to test the effects of oral magnesium supplementation on blood pressure and sodium, potassium, calcium and magnesium intraerythrocyte concentrations. Concomitantly, plasma renin activity and serum aldosterone was also measured. Oral magnesium reduced significantly the systolic (Δ = −7.6 mmHg, P < 0.05); diastolic (Δ = −3.8 mmHg, P < 0.01) and mean blood pressure (Δ = −5.9 mmHg, P < 0.01). After magnesium supplementation intraerythrocyte sodium concentration was reduced (Δ = −0.55 mEq/l per cell, P < 0.01) and intraerythrocyte magnesium concentration was increased (Δ = 1.20 mg/dl per cell, P < 0.01). The diminution of the blood pressure correlated positively with the reduction in intraerythrocyte sodium ( r = 0.66, P < 0.01) after magnesium. However, our results have shown that the blood pressure response to oral magnesium was not homogeneous. Forty percent of our patients had their blood pressure effectively controlled (more than 10 mmHg reduction in mean blood pressure), being the hypotensive effect more evident in patients with recent hypertension and in those where the reduction in intraerythrocyte sodium was significantly greater than in the non-responder individuals. Intraerythrocyte potassium and calcium, serum aldosterone, plasma renin activity and urinary sodium excretion were maintained unchanged after magnesium supplementation. These data showed that oral magnesium supplementation may reduce the blood pressure, which can be partially explained by the decrease in intracellular sodium and augment in intracellular magnesium.

Effects of magnesium on blood pressure and intracellular ion levels of Brazilian hypertensive patients

Fifteen patients with uncomplicated mild to moderate primary hypertension (7 males, 8 females, age range 36–65 years) were submitted to a double blind randomized crossover study, receiving MgO 3 times a day at a daily dose of 1.0 g (600 mg/day of magnesium) and placebo for a period of 6 weeks. This was to test the effects of oral magnesium supplementation on blood pressure and sodium, potassium, calcium and magnesium intraerythrocyte concentrations. Concomitantly, plasma renin activity and serum aldosterone was also measured. Oral magnesium reduced significantly the systolic (Δ = −7.6 mmHg, P < 0.05); diastolic (Δ = −3.8 mmHg, P < 0.01) and mean blood pressure (Δ = −5.9 mmHg, P < 0.01). After magnesium supplementation intraerythrocyte sodium concentration was reduced (Δ = −0.55 mEq/l per cell, P < 0.01) and intraerythrocyte magnesium concentration was increased (Δ = 1.20 mg/dl per cell, P < 0.01). The diminution of the blood pressure correlated positively with the reduction in intraerythrocyte sodium (r = 0.66, P < 0.01) after magnesium. However, our results have shown that the blood pressure response to oral magnesium was not homogeneous. Forty percent of our patients had their blood pressure effectively controlled (more than 10 mmHg reduction in mean blood pressure), being the hypotensive effect more evident in patients with recent hypertension and in those where the reduction in intraerythrocyte sodium was significantly greater than in the non-responder individuals. Intraerythrocyte potassium and calcium, serum aldosterone, plasma renin activity and urinary sodium excretion were maintained unchanged after magnesium supplementation. These data showed that oral magnesium supplementation may reduce the blood pressure, which can be partially explained by the decrease in intracellular sodium and augment in intracellular magnesium.

Effects of alcohol moderation on blood pressure and intracellular cations in mild essential hypertension

It is known that moderation of alcohol intake reduces blood pressure, although the exact mechanism has not yet been established. To clarify the hypotensive mechanism of alcohol reduction, we evaluated the change in cellular magnesium and sodium metabolism during alcohol reduction in mild hypertensive patients. We measured intraerythrocyte sodium and magnesium, intraplatelet free magnesium concentrations, and erythrocyte ouabain-sensitive 22Na efflux rate constant (Kos) in 17 mild essential hypertensive patients regularly consuming more than 40 g/day of alcohol, before and after 4 weeks of alcohol reduction, and 12 age-matched nondrinking hypertensives. Intraerythrocyte magnesium (P < .01) and intraplatelet free magnesium (P < .05) concentrations were significantly lower in drinkers than in nondrinkers. In drinkers, advice to reduce alcohol intake for 4 weeks resulted in a reduction in self-reported alcohol consumption from 461.7 to 71.6 g/week, a significant fall in both supine systolic blood pressure (136.3 +/- 10.8 to 130.8 +/- 11.3 mm Hg, P < .001) and supine diastolic blood pressure (85.1 +/- 8.6 to 82.6 +/- 8.7 mm Hg, P < .05). The fall in mean blood pressure correlated positively with the reduction in weekly alcohol consumption. Intraerythrocyte magnesium and Kos were increased (P < .05, P < .01, respectively), while intraerythrocyte sodium was decreased (P < .01). The increase in intraerythrocyte magnesium correlated negatively with the fall in mean blood pressure and positively with the increase in Kos, which correlated negatively with the decrease in intraerythrocyte sodium.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic heterogeneity in tubular hypomagnesemia-hypokalemia with hypocalcuria (Gitelman's syndrome)

To better clarify the genetic inheritance of primary tubular hypomagnesemia-hypokalemia with hypocalciuria, or Gitelman's syndrome (GS), we studied eight families (10 patients aged 11 to 22 years; 16 parents; 9 siblings) in which at least one offspring had GS (plasma magnesium < 0.65 mmol/liter; plasma potassium < 3.6 mmol/liter; high magnesium and potassium fractional excretions; molar urinary calcium/creatinine < 0.10). Two families each had two offspring of different sex with GS, who all had tetanic episodes and/or marked weakness during childhood or adolescence, whereas in three other families two mothers and three offspring presented GS and one father and two other offspring had hypomagnesemia and hypocalciuria but normal plasma potassium. The mean plasma magnesium and potassium levels of the patients of the first two families were significantly lower (P < 0.05) than those of the other three families. Intralymphocytic but not intraerythrocytic magnesium and potassium were significantly lower (P < 0.05) in patients compared to controls. We hypothesize that there are two different types of genetic transmission of GS, one autosomal recessive and one autosomal dominant with high phenotype variability. It seems that this genetic heterogeneity is associated with a different clinical expression with frequent tetanic episodes and lower plasma potassium and magnesium levels in the autosomal recessive form.

Metabolic Effects of Inhaled Fenoterol in Normal Subjects

Although the hypokalemic effect of inhaled beta 2-adrenergic agonists has been well documented, little is known as to their effect on plasma magnesium. We therefore examined in ten healthy young volunteers the effect of the inhalation of 2 mg of nebulized fenoterol on plasma potassium (Kpl), plasma magnesium (Mgpl), and intraerythrocytic magnesium (MgIE) levels, as well as on plasma insulin and C peptide concentrations, measured before and serially up to 110 min after fenoterol inhalation. In all subjects, fenoterol inhalation caused a reversible reduction in Kpl (range, 0.2 to 1.1 mEq/L), which was progressive, reaching a statistically significant nadir 30 to 60 min following fenoterol inhalation (largest dip in Kpl, 0.55 +/- 0.29 mEq/L; p < 0.05). The nadir in Kpl levels was preceded by a peak in plasma insulin levels in all subjects. No significant changes in Mgpl or MgIE were observed in any of the subjects. We conclude that fenoterol inhaled at a dosage used in clinical practice significantly reduces Kpl but not Mgpl nor MgIE levels in healthy subjects, indicating a lower sensitivity of Mg++ ions to beta 2-adrenergic stimulation than K+ ions. Beta 2-adrenergic-induced insulin secretion probably contributes to the hypokalemic effect of inhaled fenoterol.

Decreased Platelet Free Magnesium with Increased Free Calcium in Mild Essential Hypertension.

Intracellular free magnesium and calcium concentrations of platelets from 21 mild essential hypertensive patients and 8 normotensive individuals were measured using mag-fura2, a recently developed fluorescent indicator, and fura2, respectively. Compared with normotensives, intracellular free magnesium concentration was significantly decreased (0.32±0.10 vs. 0.50±0.15mmol/l, mean±SD, p<0.001) and intracellular free calcium concentration was significantly increased (40.2±9.0 vs. 21.7±11.8 nmol/l, p<0.001) in the hypertensives. In all subjects, mean blood pressure correlated negatively with intracellular free magnesium (r=-0.57, p<0.001) and positively with intracellular free calcium (r=0.48, p<0.02). Furthermore, intracellular free magnesium correlated negatively with intracellular free calcium. In contrast, serum and intraerythrocyte magnesium concentrations did not differ between the two groups. These results suggest that the decreased intracellular free magnesium of platelets concomitant with the increased intracellular free calcium may participate in the pathophysiology of essential hypertension. (Hypertens Res 1992; 15: 105-110)

Genetic traits related to hypertension and electrolyte metabolism.

The genetic and cultural heritability and intercorrelation of traits related to hypertension have been carried out in 98 Utah pedigrees (2,500 person) and 58 sibships with two or more hypertensive persons (131 hypertensive persons). Although none of these traits has been established as a marker for "sodium-sensitive hypertension," many of them are related at least indirectly to both electrolyte metabolism and risk of hypertension. Significant recessive monogenic effects and high total heritability (52-84%) were found for urinary kallikrein, high fat pattern index, intraerythrocytic sodium, Na-Li countertransport, and ouabain binding sites. Familial correlations more strongly attributable to shared environment than to genetic effects were found for Na,K-ATPase pump activity, intraerythrocytic magnesium, plasma digoxin-like factor, plasma renin activity, and plasma sodium concentration. All anthropometric variables tested showed highly significant genetic heritability with low and insignificant shared family environmental effects. Several of the genetically determined cellular cation tests also correlated with other genetic traits including plasma lipids, anthropometric measurements, and other cellular cation tests. Among hypertensive individuals with familial dyslipidemic hypertension, plasma insulin levels correlated with obesity and lipid abnormalities and with several cellular cation flux tests associated with hypertension.

Increased Erythrocyte Magnesium in Never Treated Essential Hypertension

In the present study we aimed at evaluating the intracellular concentrations of magnesium, potassium and sodium in 50-year-old, otherwise healthy white men with never treated, essential hypertension (n = 12) and in normotensive control subjects (n = 12) matched for age, sex, race, height, weight and smoking habits. Intraerythrocyte magnesium was significantly increased in the hypertensive group (P less than .001) and correlated positively and significantly to blood pressure in the total group (P less than .01). The intracellular potassium to sodium ratio tended to be lower in the hypertensive group (P less than .05). Thus, the present study supports increased intracellular magnesium probably unrelated to intracellular potassium-sodium imbalance in never treated, essential hypertension.

Plasma and intracellular Mg2+ concentrations in pre-eclampsia

Plasma and intra-erythrocytic magnesium concentrations were determined in 27 patients with pre-eclampsia and in 22 healthy pregnant women. In the pre-eclamptic women, the Mg2+ concentrations were measured before and after treatment with Mg2+ salts and after delivery. The plasma Mg2+ concentration was not significantly different in the pre-eclamptic and the healthy pregnant women. The intra-erythrocytic Mg2+ concentration before treatment with Mg2+ was significantly lower in the pre-eclamptic patients than in the healthy pregnant women [1.33 +/- 0.29 versus 1.01 +/- 0.16 mmol/l (means +/- s.d.); P less than 0.05] and increased after treatment with Mg2+ to 1.19 +/- 0.24 mmol/l. Lowered cellular Mg2+ concentrations in pre-eclampsia may contribute to the development of hypertension in this disorder.

Dietary linoleic acid prevents the development of deoxycorticosterone acetate-salt hypertension.

The aim of this study was to elucidate the effect of dietary variations of linoleic acid on the development of deoxycorticosterone acetate (DOCA)-salt hypertension in rats. All rats were divided into three groups and fed one of the following isocaloric diets with 8% NaCl: a high linoleic acid (HLA) (20% sunflower oil), a moderate linoleic acid (5% lard oil + 15% sunflower oil), or a low linoleic acid (DLA) (20% lard oil). After 4 weeks of feeding, we determined intraerythrocyte sodium, potassium, and magnesium concentrations, intra-aortic and lymphocyte magnesium content, and erythrocyte ouabain-sensitive 22Na efflux rate constant. Cytoplasmic free calcium concentration of lymphocytes from thymus was also determined with quin-2 as a fluorescent indicator. In the HLA group, the elevation of systolic blood pressure was significantly attenuated, and intraerythrocyte sodium concentration was significantly lower than in the DLA group. There were greater intraerythrocyte potassium and magnesium concentrations, intra-aortic and lymphocyte magnesium contents, and erythrocyte ouabain-sensitive 22Na efflux rate constant in the HLA group as compared with other groups. Cytoplasmic free calcium concentration in the HLA group was significantly lower than in other groups. Systolic blood pressure significantly correlated negatively with intraerythrocyte and intra-aortic magnesium concentrations and intraerythrocyte potassium concentration, and correlated positively with cytoplasmic free calcium concentration. Erythrocyte ouabain-sensitive 22Na efflux rate constant significantly correlated positively with intraerythrocyte magnesium concentration. These findings suggest that dietary linoleic acid can attenuate the development of DOCA-salt hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Oral magnesium supplementation in patients with essential hypertension.

To elucidate the effects of magnesium on high blood pressure, a 4-week study of oral magnesium supplementation (MgO 1 g/day) was conducted in 21 outpatients with uncomplicated essential hypertension. During the study, blood pressure and intraerythrocyte sodium concentration decreased significantly, and the erythrocyte ouabain-sensitive 22Na efflux rate constant (Kos) and intraerythrocyte magnesium concentration both increased. Serum triglyceride and free fatty acid concentrations were reduced. Furthermore, the elevation in Kos significantly and positively correlated with both the increase in intraerythrocyte magnesium concentration and the decrease in mean blood pressure. There was a significant inverse correlation between the prestudy Kos and the decrease in mean blood pressure. In addition, when patients were divided according to their overall decrease in mean blood pressure, the prestudy intraerythrocyte sodium concentration was significantly higher in patients with a mean blood pressure decrease of more than 7 mm Hg than that of patients whose mean blood pressure decrease was less than 7 mm Hg. These results suggest that oral magnesium supplementation may lower blood pressure through the activation of a cell membrane sodium pump and may reduce serum lipid concentration. It also suggests that the lower the prestudy Kos or the higher the prestudy intraerythrocyte sodium concentration, the more effective the oral magnesium treatment is in lowering blood pressure. Therefore, we concluded that appropriate oral magnesium intake might be effective as a nonpharmacological treatment for essential hypertension.

Effects of oral magnesium on blood pressure and red cell sodium transport in patients receiving long-term thiazide diuretics for hypertension.

Twenty patients receiving long-term (1.0 to 10.3 years) thiazide diuretic treatment for essential hypertension (Th group) received magnesium supplementation as MgO (600 mg Mg/day) for 4 weeks and placebo for another 4 weeks. Before and at the end of each period, we measured blood pressure; intraerythrocyte magnesium, sodium, and potassium (R-Mg, R-Na, and R-K); and erythrocyte ouabain (10-4 M) sensitive sodium efflux rate constant (Kos). The same measurements were also performed in 21 untreated age-matched essential hypertensives (EHT group). In the Th group, R-Mg was lower, R-Na was higher, and Kos was lower than in the EHT group before magnesium supplementation. Oral magnesium resulted in a significant increase in R-Mg (p less than 0.005) and a decrease in R-Na (p less than 0.01), together with an increase in Kos (p less than 0.005) in the Th group. During magnesium supplementation, the increased Kos was correlated negatively with the lowered R-Na (r = -0.57, p less than 0.01) and positively with the increased R-Mg (r = 0.61, p less than 0.005). Systolic, diastolic, and mean blood pressures were reduced significantly during magnesium administration by a mean of 7.5, 3.0, and 4.5 mm Hg. The results indicate that long-term diuretic treatment may give rise to an intracellular magnesium deficiency and a suppression in cell membrane active transport for sodium, with a resultant increase in intracellular sodium content.(ABSTRACT TRUNCATED AT 250 WORDS)