A compartmental model of magnesium metabolism in healthy men based on two stable isotope tracers

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology Vol. 54; no. 3; pp. R656 - R663
• Main Authors: SABATIER, Magalie, PONT, Frédéric, ARNAUD, Maurice J, TURNLUND, Judith R
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Physiological Society 01.09.2003
• Subjects: Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Health; Intravenous administration; Magnesium; Mass spectrometry; Men; Metabolism; Metabolisms and neurohumoral controls; Stable isotopes; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Water and mineral metabolism. Osmoregulation. Acidobasic balance; Human; Excretion; Compartmental model; inductively coupled plasma-mass spectrometry; magnesium absorption; Kinetics; Magnesium; Metabolism; magnesium fecal endogenous excretion; Inorganic element; Mass spectrometry
• ISSN: 0363-6119; 1522-1490

The aim of this study was to build a compartmental model of magnesium (Mg) kinetics by using data collected from six healthy adult men after oral administration of 26Mg and intravenous administration of 25Mg. Blood, urine, and feces were collected for 12 days after administration of the isotopes. Isotopic ratios were determined by inductively coupled plasma-mass spectrometry. Data were analyzed for each subject using SAAMII. We began with a compartmental model previously proposed (Avioli LV and Berman M. J Appl Physiol 21: 1688-1694, 1966) and developed an alternative approach to resolve the discrepancy between model-predicted curves and experimental data. This analysis enables the exploration of 25% of total body Mg that exchanges rapidly from plasma compartment with two extraplasma pools. One of the extraplasma compartments contains 80% of the exchangeable Mg with a transport rate of 48 ± 13 mg/h. The second exchanges 179 ± 88 mg of Mg/h. The model permitted estimation of kinetic parameters as well as fractional Mg absorption and fecal endogenous excretion.