Calcitonin
|
|
Calcitonin is a a 32 amino acid polypeptide hormone that is produced in humans primarily by the C cells of the thyroid, and in many other animals in the ultimobrachial body.
| Contents |
Synthesis
It is formed by proteolytic cleavage of a larger prepropeptide which is the product of the CALC1 gene, which itself is part of a superfamily of related protein hormone precusors including Islet Amyloid Precursor Protein, Calcitonin Gene-Related Peptide and the precursor of Adrenomedullin.
Physiology
The hormone participates in calcium and phosphorus metabolism and it was found in fish, reptiles, birds and mammals.
Specifically, calcitonin reduces blood calcium levels in three ways:
- decreasing calcium absorption by the intestines
- decreasing osteoclast activity in bones
- decreasing calcium reabsorption by the kidney tubules
Pharmacology
Salmon calcitonin is used for the treatment of:
- postmenopausal osteoporosis
- hypercalcaemia
- Paget's disease
- bone metastases
History
Calcitonin was purified in 1962 by Copp and Cheney. While it was initially considered a secretion of the parathyroid glands, it was later identified as the secretion of the C-cells (parafollicular cells) of the thyroid.
Reference
- Copp DH, Cheney B. Calcitonin-a hormone from the parathyroid which lowers the calcium-level of the blood. Nature 1962;193:381-2. PMID 13881213fr:Calcitonine