Parathyroid Hormone

The hormone parathyroid hormone (PTH) is produced in the parathyroid gland and is released in the blood when there is a calcium deficiency - the hormone signal releases more calcium from the bone. In this way, parathyroid hormone promotes, among other things, the osteoclasts that break down bones.

https://de.wikipedia.org/wiki/Parathormon sub>(Wikipedia CC-by-sa-3.0)