Cellular magnesium acquisition : an anomaly in embryonic cation homeostasis
Citable URI
https://hdl.handle.net/1912/1927As published
https://doi.org/10.1016/j.yexmp.2007.03.007Keyword
Magnesium; Cation transporters; Effect of fluoride on metabolism; Early embryo homeostasis; Yolk ion partition; Ionic competition; Sodium; Potassium; Calcium; Teleost embryos; Fundulus heteroclitus; Analytic methodologyAbstract
The intracellular dominance of magnesium ion makes clinical assessment difficult despite the critical role of Mg++ in many key functions of cells and enzymes. There is general consensus that serum Mg++ levels are not representative of the growing number of conditions for which magnesium is known to be important. There is no consensus method or sample source for testing for clinical purposes. High intracellular Mg++ in vertebrate embryos results in part from interactions of cations which influence cell membrane transport systems. These are functionally competent from the earliest stages, at least transiently held over from the unfertilized ovum. Kinetic studies with radiotracer cations, osmolar variations, media lacking one or more of the four biological cations, Na+, Mg++, K+, and Ca++, and metabolic poison 0.05 mEq/L NaF, demonstrated: (1) all four cations influence the behavior of the others, and (2) energy is required for uptake and efflux on different time scales, some against gradient. Na+ uptake is energy dependent against an efflux gradient. The rate of K+ loss is equal with or without fluoride, suggesting a lack of an energy requirement at these stages. Ca++ efflux took twice as long in the presence of fluoride, likely due in part to intracellular binding. Mg++ is anomalous in that early teleost vertebrate embryos have an intracellular content exceeding the surrounding sea water, an isolated unaffected yolk compartment, and a clear requirement for energy for both uptake and efflux. The physiological, pathological, and therapeutic roles of magnesium are poorly understood. This will change: (1) when 28Mg is once again generally available at a reasonable cost for both basic research and clinical assessment, and (2) when serum or plasma levels are determined simultaneously with intracellular values, preferably as part of complete four cation profiles. Atomic absorption spectrophotometry, energy-dispersive x-ray analysis, and inductively coupled plasma emission spectroscopy on sublingual mucosal and peripheral blood samples are potential methods of value for coordinated assessments.
Description
Author Posting. © The Author(s), 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Experimental and Molecular Pathology 83 (2007): 224-240, doi:10.1016/j.yexmp.2007.03.007.
Collections
Suggested Citation
Preprint: Shanklin, D. Radford, "Cellular magnesium acquisition : an anomaly in embryonic cation homeostasis", 2007-03-14, https://doi.org/10.1016/j.yexmp.2007.03.007, https://hdl.handle.net/1912/1927Related items
Showing items related by title, author, creator and subject.
-
Magnesium isotopic composition of the oceanic mantle and oceanic Mg cycling
Liu, Ping-Ping; Teng, Fang-Zhen; Dick, Henry J. B.; Zhou, Mei-Fu; Chung, Sun-Lin (2017-02)To constrain the Mg isotopic composition of the oceanic mantle, investigate Mg isotope fractionation of abyssal peridotites during seafloor alteration, and assess Mg budget in the oceans, a suite of 32 abyssal peridotite ... -
Diel plant water use and competitive soil cation exchange interact to enhance NH4+ and K+ availability in the rhizosphere
Espeleta, Javier F.; Cardon, Zoe G.; Mayer, K. Ulrich; Neumann, Rebecca B. (Springer, 2016-11-12)Hydro-biogeochemical processes in the rhizosphere regulate nutrient and water availability, and thus ecosystem productivity. We hypothesized that two such processes often neglected in rhizosphere models — diel plant water ... -
Responses of soil carbon, nitrogen and cations to the frequency and seasonality of prescribed burning in a Cape Cod oak-pine forest
Neill, Christopher; Patterson, William A.; Crary, David W. (2007-05-09)Fire is an important component of the historic disturbance regime of oak and pine forests that occupy sandy soils of the coastal outwash plain of the northeastern U.S. Today prescribed fire is used for fuel reduction and ...