Renal Handling of Calcium

The amount of calcium contained in the body of vertebrate mammals is prominently large when compared to other minerals. For example, total body calcium amounts to 600,000mEq, whereas sodium amounts to 3,500mEq [1]. Most of the calcium exists in bone in the form of hydroxyapatite and only 1% of the calcium is present in extracellular fluid [1]. The regulation of extracellular calcium is critical for many physiological processes and is complex. However, homeostasis is achieved by the cooperative interaction between the parathyroid gland, intestine, kidney, and bone. In this chapter, the mechanism and regulation of calcium handling in the kidney is discussed.