What hormone regulates blood calcium levels?

The parathyroid hormone regulates the blood levels of calcium. The hormone helps keep the calcium levels constant as it acts on kidneys, intestines and bones.

Maintaining a level blood calcium concentration is crucial to the function of nerves and muscle contractions. The parathyroid hormone, or PTH, is excreted from the parathyroid glands when blood calcium levels drop. The bones, intestines and kidneys are targeted during the release of PTH. The function of PTH varies, but in general, the hormone helps to stimulate reabsorption of the calcium and acts as a trigger to increase calcium absorption in the intestines. When the blood calcium levels rise, the PTH release is inhibited.