Somatomedin is a group of hormones that is produced, when stimulated by somatotropin (STH), to promote cell growth and division. In this way, they mediate the effect of somatotropin (also known as growth hormone ).
They have similar biological effects to somatotropin.
Somatomedins also stimulates Somatostatin production. Somatostatin suppresses growth hormone release. So, levels of somatomedin and growth hormone are controlled via negative feedback. When somatomedin levels are high, they reduce growth hormone levels by stimulating somatostatin production. Initially somatomedins were thought to be produced in the liver in response to a GH stimulus. It is now known that somatomedins are produced in many tissues, and many actions are autocrine or paracrine. The liver is probably the predominant source of circulating somatomedin. So, a high level of somatomedins means a high level of growth hormone. And when this happens, somatomedins lower the level of growth hormone by stimulating somatostatin.
Three forms include:
- somatomedin A, which is another name for insulin-like growth factor 2
- somatomedin B, which is derived from vitronectin
- somatomedin C, which is another name for insulin-like growth factor 1
- Somatomedin at eMedicine Dictionary
- growth+hormone at eMedicine Dictionary
- Berner Levy Physiology 6th edition|page=723|
- Zhou A (2007). "Functional structure of the somatomedin B domain of vitronectin". Protein Science 16 (7): 1502. doi:10.1110/ps.072819107. PMC 2206693. PMID 17567740.
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