Magnesium Homeostasis

Magnesium is essential for a vast number of cellular processes, including energy metabolism, protein and nucleic acid synthesis, and in the maintenance of the electrical potential of nervous tissues and cell membranes. The symptoms of hypomagnesemia depend on its severity and rate of onset. Symptoms include fatigue and leg cramps in mild hypomagnesemia, and seizures, coma, and death in severely deficient states. In the presence of hypermagnesemia, the fractional excretion of magnesium is enhanced in order to maintain normal serum magnesium. Clinically, hypermagnesemia is associated with gastrointestinal symptoms including nausea and vomiting. The calcium sensing receptor (CaSR) senses extracellular calcium as well as magnesium concentrations in the distal nephron as well as in other tissues and thereby plays an essential role in calcium and magnesium homeostasis. In the parathyroid, the CaSR is responsible for adjusting the rate of PTH synthesis and release to the extracellular levels of calcium and magnesium.