The parathyroid glands produce a hormone called parathyroid hormone which controls levels of calcium in the blood. The parathyroid glands are small pea-sized glands located in the neck just behind the butterfly-shaped thyroid gland. Most people have four parathyroid glands, with two parathyroid glands lying behind each ‘wing’ of the thyroid gland.
The main target organs where parathyroid hormone exerts its effects are the bones and the kidneys. As and when required, parathyroid hormone is released by the parathyroid glands into the blood and causes the bones to release calcium and increase levels in the bloodstream. It also causes the kidneys to stop calcium being lost in urine as well as stimulating the kidneys to regulate vitamin D metabolism. If someone does not take in enough calcium through their diet or does not have enough vitamin D, the circulating calcium levels fall and the parathyroid glands produce more parathyroid hormone. This brings calcium levels in the bloodstream back up to normal.
Another method that parathyroid hormone uses to increase calcium levels in the bloodstream is activation of vitamin D. This occurs in the kidney too; the activated vitamin D then increases calcium absorption from the gut.
Calcitonin is a hormone which is released by thyroid cells to regulate calcium and phosphorus in the body. It counterbalances the effect of Parathyroid hormone.
Prostaglandins (PG) are abundantly produced in the kidney and play an important role in triggering the inflammatory response, contributing to the occurrence and progression of kidney diseases. PGs exert essential functions in the regulation of renal hemodynamics, renin enzyme release, as well as water and salt balance.