Parathyroid hormone
Parathyroid hormone (PTH), also called parathormone or parathyrin, is a hormone secreted by the parathyroid glands. This hormone regulates the serum calcium and phosphate concentration through its effects on bone, kidney, and intestine.
When calcium levels are too low, the glands release PTH to bring the calcium levels back up into a normal range. When your calcium levels rise, the glands stop releasing PTH.