Calcium, phosphate, and magnesium are multivalent cations that are important for many
biologic and cellular functions. The kidneys play a central role in the homeostasis of these
ions. Gastrointestinal absorption is balanced by renal excretion. When body stores of these
ions decline significantly, gastrointestinal absorption, bone resorption, and renal tubular
reabsorption increase to normalize their levels. Renal regulation of these ions occurs
through glomerular filtration and tubular reabsorption and/or secretion and is therefore an …