Parathyroid hormone receptor

Parathyroid hormone receptor (PTH receptor) is a type of protein that is located on the surface of cells and interacts with parathyroid hormone (PTH). This interaction plays a crucial role in the regulation of calcium and phosphate metabolism in the body. The PTH receptor is a member of the G protein-coupled receptor (GPCR) family, which is a large group of proteins that play a role in many different physiological functions.

Structure

The PTH receptor is a transmembrane protein, meaning it spans the entire width of the cell membrane. It consists of seven transmembrane domains, which are characteristic of GPCRs. The extracellular portion of the receptor is responsible for binding to PTH, while the intracellular portion interacts with G proteins to initiate a cellular response.

Function

The primary function of the PTH receptor is to mediate the effects of PTH, which is a hormone secreted by the parathyroid glands. PTH acts to increase the concentration of calcium in the blood, and it does this by acting on the PTH receptor in three main tissues: the kidneys, the bones, and the intestine.

In the kidneys, PTH stimulates the reabsorption of calcium and the excretion of phosphate. In the bones, it stimulates the release of calcium and phosphate from the bone matrix. In the intestine, although PTH does not directly act on the PTH receptor, it increases calcium absorption indirectly by stimulating the production of vitamin D.

Clinical significance

Mutations in the PTH receptor can lead to a variety of disorders. For example, Jansen's metaphyseal chondrodysplasia is a rare genetic disorder caused by a mutation in the PTH receptor that results in constitutive activation of the receptor. This leads to abnormalities in bone development.

On the other hand, Pseudohypoparathyroidism type 1a is a disorder caused by mutations in the G protein that interacts with the PTH receptor, leading to resistance to the actions of PTH.

See also

• Parathyroid hormone
• G protein-coupled receptor
• Calcium metabolism
• Phosphate metabolism