Intracellular free magnesium concentrations in skeletal muscle in chronic uraemia

Low intracellular free magnesium concentrations ([Mg2+]i) are associated with essential hypertension and may reflect a disordered cellular ionic environment. 31P magnetic resonance spectroscopy was used to study skeletal muscle [Mg2+]i in a group of chronic renal failure (CRF) patients and data were compared with a group of control subjects of similar age. Other data including the patients' blood pressure, medication and plasma biochemistry were collected. There was a significant inverse correlation of [Mg2+]i with systolic (p < 0.001) and diastolic blood pressure (p < 0.05) in the CRF population. In CRF [Mg2+]i was similar (0.52 +/- 0.01 mM, SEM) to controls (0.53 +/- 0.01 mM; p = 0.20), even if just the normotensive patients and controls were compared. There was no correlation of [Mg2+]i with plasma parathyroid hormone, total [Mg2+] or [Ca2+]. Similar to studies in subjects with essential hypertension, these data support a role for [Mg2+]i specifically, and an abnormal intracellular environment more generally, in the pathophysiology of hypertension in CRF.