The three points of calcium flux, the intestine, the kidneys, and the bone, are all regulated and can modify their normal exchange rates in response to metabolic demands.

Should a drop in the concentration of serum calcium occur—or, more specifically, a drop in the concentration of biologically active, ionized calcium—the kidneys can retain a greater percentage of the serum calcium they receive for filtration. Similarly, bone can also assist in regulating serum calcium by mobilizing skeletal calcium through the resorption of mineralized bone matrix.