Well, the function of the parathyroid hormone is basically the opposite of calcitonin. So previously we discussed a hormone that is produced by the thyroid gland known as calcitonin. And calcitonin is responsible for decreasing the concentration of calcium inside our blood. What the parathyroid hormone does is it increases the concentration of our calcium inside our blood. So this type of hormone is responsible for maintaining and regulating the concentration of calcium inside our blood. Now, the release or inhibition of the parathyroid hormone is controlled by the concentration of calcium inside of our blood.