Parathyroid hormone is involved in the metabolism of ___ .

As the blood filters through the parathyroid glands, they detect the amount of calcium present in the blood and react by making more or less parathyroid hormone (PTH). When the calcium level in the blood is too low, the cells of the parathyroids sense it and make more parathyroid hormone. Thus, parathyroid hormone is involved in the metabolism of calcium.