Parathormone
Parathormone (PTH), also referred to as parathyroid hormone, is a hormone found in the human body. It is secreted by the parathyroid glands. PTH is a polypeptide hormone containing between 83 and 85 amino acids. It is classified as a peptide hormone.
Secretion and Production
PTH is produced in and excreted from the parathyroid gland. It regulates calcium metabolism in conjunction with calcitonin. The primary effect of PTH is an increase in the concentration of calcium in the blood. It does this in three ways: it enhances the release of calcium from the large reservoir contained in the bones, enhances reabsorption of calcium from renal tubules, and enhances the absorption of calcium in the intestine by increasing the production of vitamin D. PTH is unable to regulate the absorption and mobilization of calcium in the absence of vitamin D.
PTH keeps blood-calcium at its normal level while calcitonin ensures that the level of blood-calcium does not rise too high. Other effects of PTH secretion include both promotion of the formation of bone tissue and control over the level of magnesium in the blood plasma.
Pharmacological Uses
A synthetic form of PTH is available for medical use. It must be injected via syringe. There are two common uses of synthetic PTH treatment:
Osteoporosis
Because PTH helps to grow new bone, it is commonly used as an osteoporosis treatment. Synthetic PTH can cause new bone growth as well as help to maintain bone mass and prevent future bone loss.
Hypoparathyroidism
Hypoparathyroidism is a condition in which the body produces and secreted insufficient amounts of PTH, generally as a result of a surgical mishap resulting in loss of normal parathyroid function, autoimmune disorder, or birth defect. In this case, synthetic PTH can be administered in order to restore normal PTH production and secretion.