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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #128427
Title: EXCHANGEABLE MAGNESIUM POOL MASSES REFLECT THE MAGNESIUM STATUS OF RATS

Author
item FEILLET-COUDRAY, CHRISTINE - BAYLOR COLLEGE MED
item COUDRAY, CHARLES - BAYLOR COLLEGE MED
item BRULE, FABIENNE - BAYLOR COLLEGE MED
item GUEUX, ELYETT - BAYLOR COLLEGE MED
item MAZUR, ANDRZEJ - BAYLOR COLLEGE MED
item Abrams, Steven
item RAYSSIGUIER, YVES - BAYLOR COLLEGE MED

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/25/2000
Publication Date: 9/1/2000
Citation: Feillet-Coudray,C., Coudray,C., Brule,F., Gueux,E., Mazur A., Abrams,S.A., Rayssiguier,Y. 2000. Exchangeable Magnesium Pool Masses Reflect the Magnesium Status of Rats. 130(9):2306-2311.

Interpretive Summary: Magnesium (Mg) is a biologically essential nutrient. Mg depletion has been reported in chronic illnesses like diabetes and heart disease. A marginal Mg dietary intake may induce high Mg deficiency. Unfortunately, current methods or "markers" of assessing a person's Mg status are inadequate because they are not sufficiently sensitive. We fed rats a control diet, a marginally deficient Mg diet, or a severely deficient Mg diet for 2 weeks. Then we injected them with an Mg stable isotope and watched what happened in their bloodstream. We used two methods of analysis. Our results showed that the exchangeable pools of Mg constitute a good marker of Mg status in rats. While compartmental analysis is a more accurate assessment of Mg exchangeable pools, it is easier and quicker to determine the combined pools of Mg that exchange with the blood Mg within 48 hours. This study is very useful because it shows doctors good ways to accurately assess Mg status in humans, to help guard against related illnesses.

Technical Abstract: A sensitive and valid marker to assess magnesium (Mg) status in humans is not available. The kinetically determined exchangeable pool masses have been used for other minerals, as markers of whole-body mineral status. To evaluate the validity of this relationship for Mg, we measured the exchangeable pools of Mg in rats over a range of Mg dietary intakes. Rats weighing ~170g were fed a control diet (500mg Mg/kg), a marginally Mg- deficient diet (200mg/kg) or a severely Mg-deficient (60mg Mg/kg) for 2wk. Rates administered in intravenously of **25Mg, and plasma **25Mg disappearance curve followed for 7d. 2 methods were used to analyze the exchangeable pools of Mg: 1)formula compartmental modeling and 2)a simplified determination of total mass of the rapidly exchangeable Mg pool (EMgP). The mass of 2 extracellular and 1 intracellular exchangeable pools determined by compartmental analysis decreased in proportion to dietary Mg intake. EMgP the combined pools of Mg that exchange with the plasma Mg within 48h, decreased as dietary Mg was lowered. It was correlated with conventional markers of Mg status. Compartmental analysis assesses Mg exchangeable pools more accurately, but determination of EMgP is faster. Our findings demonstrate the exchangeable pools of Mg constitute a good marker of Mg status in rats.