151. Feasibility of measuring organ magnesium turnover in vivo by continuous feeding of a stable isotope
- Author
-
Susanne Hartmann, Bill T. G. Ting, Morteza Janghorbani, and Sally A. Schuette
- Subjects
Nutrition and Dietetics ,Chemistry ,Ratón ,Stable isotope ratio ,Magnesium ,Endocrinology, Diabetes and Metabolism ,Clinical Biochemistry ,Skeletal muscle ,chemistry.chemical_element ,Endogeny ,Metabolism ,Isotope dilution ,Biochemistry ,medicine.anatomical_structure ,Animal science ,In vivo ,medicine ,Molecular Biology - Abstract
The feasibility of measuring organ endogenous magnesium (Mg en ) turnover in vivo by continuous feeding of a single stable isotope of Mg was demonstrated in this investigation. Adult CD-1 mice were fed a Mg deficient diet and deionized water with (+Mg) or without (−Mg) added 24 Mg (290 μg/mL) for 16 days. The change in organ 25 Mg content over time was then accurately determined by in vitro isotope dilution with 26 Mg as spike. Organ endogenous Mg content was then calculated as 25 Mg en / 0.1028 and exogenous Mg (Mg ex ) content from the expression Mg ex = Mg total - Mg en . All soft tissues examined in the +Mg group showed significant turnover of Mg en and accumulation of Mg ex . The rate at which this occurred was organ specific. Apparent half-lives for Mg en turnover were 3.83, 4.13, 5.87, and 8.77 days for liver, heart, brain, and skeletal muscle, respectively. Mg restriction resulted in a dramatic decrease in the rate of Mg en turnover with apparent half-lives ranging from 60.3 to 146 days. Brain showed the smallest decrease in Mg en turnover with Mg restriction, and was the only tissue observed to lose a significant amount of total Mg.
- Published
- 1992
- Full Text
- View/download PDF