Alteration in Mg2+ content of red blood cells from patients with diuretic therapy

Lowered Total Intracellular Magnesium Status in a Subgroup of Hypertensives

A new method to determine total Mg++ content in lymphocytes was developed, offering advantages for routine measurements as compared to fluorescence methods. Intracellular total Mg++ measurements were performed in lymphocytes of 18 healthy subjects and 19 untreated essential hypertensive patients. Mg++ content was referred to lymphocytic and membrane protein, which was determined according to Bradford's method. Mg++ measurements were performed by atomic absorption spectroscopy using a Video 12 apparatus of Thermo Electron Instrumentation Laboratory, Andover, USA. The results show that in patients with essential hypertension total intralymphocytic Mg++ content is significantly lower (0.07 +/- 0.05 mmol/g lymphocytic protein, mean +/- s.d.) as compared to controls (0.11 +/- 0.04 mmol/g lymphocytic protein, mean +/- s.d., p < 0.05). Free intracellular Mg++ content was measured in lymphocytes by the fluorescent indicator mag-fura-II, showing no significant differences in normotensives and hypertensives (0.30 +/- 0.16 versus 0.38 +/- 0.17 mmol/l). Additionally, in platelets free intracellular Mg++ concentrations were not found of significant difference in normotensives and hypertensives (0.52 +/- 0.23 versus 0.47 +/- 0.27 mmol/l) using mag-fura-II. In plasma Mg++ concentrations there was no significant difference in the normotensive and hypertensive group (0.92 +/- 0.07 versus 0.88 +/- 0.07 mmol/l). There was no correlation between plasma or free or total cellular magnesium concentrations in both groups. Furthermore this method seems also suitable for routine measurements of total intracellular Mg++ concentrations in even larger measurements like mag-fur-II. Lowered total intracellular Mg++ concentrations in a subgroup of primary hypertensives may contribute to the development of this disorder, perhaps due to different buffering systems.http://link.springer-ny.com/link/service/journals/00547/bibs/8n3p154.html

Electron-probe X-ray Microanalysis of Magnesium and Sodium Ion Content in Vascular Smooth Muscle Cells from Spontaneously Hypertensive and Normotensive Rats

Whereas in blood cells decreased magnesium concentrations and increased sodium concentrations in essential hypertension have often been described, only sparse data exist on cellular magnesium or sodium content in vascular smooth muscle cells. Therefore, in aortic smooth muscle cells from seven spontaneously hypertensive rats (SHR) of the Münster strain and seven normotensive Wistar-Kyoto rats (WKY), the intracellular magnesium and sodium content were measured by electron-probe X-ray microanalysis. Measurements were performed in aortic cryosections 3 µm thick. The magnesium ion content was 0.93 +/- 0.17 g/kg dry weight in SHR vs 1.14 +/- 0.12 g/kg dry weight in WKY (p < 0.05). Vascular smooth muscle sodium ion content was measured at 6.85 +/- 0.59 g/kg dry weight in WKY and 12.47 +/- 1.62 g/kg dry weight in SHR (p < 0.05). In conclusion, aortic smooth muscle cells from SHR are characterized by a markedly lowered intracellular magnesium ion content and increased sodium ion concentrations compared with normotensive cells. The results may be due to genetically determined disturbances in transmembrane magnesium and sodium ion transport. Cellular magnesium and sodium handling may be disturbed in SHR aortic smooth muscle as it is in hypertensive blood cells.