Parathyrin

Parathyrin (also known as Parathyroid hormone or PTH) is a hormone secreted by the parathyroid glands that regulates the serum calcium through its effects on bone, kidney, and the intestine.

Function

Parathyrin plays a crucial role in bone remodeling, which is an ongoing process in which bone tissue is alternately resorbed and rebuilt over time. PTH is secreted in response to low blood serum calcium (Ca2+) levels. PTH indirectly stimulates osteoclast activity within the bone matrix (osteon), in an effort to release more ionic calcium (Ca2+) into the blood to elevate a low serum calcium level to normal.

Structure

Parathyrin is a protein hormone and is composed of 84 amino acids. It is synthesized as a preprohormone of 115 amino acids which is cleaved to proPTH of 90 amino acids and then to the hormone of 84 amino acids.

Clinical significance

Abnormalities associated with parathyrin can lead to a variety of health problems. Overproduction of parathyrin (hyperparathyroidism) can result in fatigue, depression, constipation, nausea, vomiting, and other symptoms. Underproduction (hypoparathyroidism) can result in numbness, muscle cramps, and spasms.

See also

• Hyperparathyroidism
• Hypoparathyroidism
• Calcium metabolism
• Parathyroid gland

Parathyrin Resources
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