Bone mineral plays a very important role in body electrolyte and acid-base metabolism. The huge amounts of electrolyte contained in the skeleton are listed in the Table. While the subjects of calcium and phosphorus metabolism and metabolic bone diseases have been well reviewed1-3 and the concentration of many elements in human bone has been determined,4,5 the function of bone in sodium, potassium, magnesium, and acid-base metabolism has been neglected. It is the purpose of this review to consider these subjects.
The average human adult body contains about 3,000-3,500 mEq. of sodium. Approximately 35%-40% of this, or about 1,400 mEq., exists in the skeleton.7,9,10 Of the sodium in the adult skeleton, about 30% is rapidly exchangeable with radioactive sodium11 and is therefore in continuous dynamic equilibrium with the extracellular fluid.Many factors have been shown to change the sodium concentration of bone. As the sodium concentration