QS Study

Somatomedins are polypeptide growth factor secreted by the liver and other tissues. It is a hormone which acts as an intermediary in the stimulation of tissue growth by growth hormone. It is a type of growth factor and a type of cytokine.

Function:

Somatomedins have a potent effect of increasing all aspect of bone growth. They are produced in many tissues and have autocrine and paracrine actions in addition to their endocrine action.

Many of the somatomedins have effects on growth which are similar to the effect of insulin on growth. So it is called insulin-like growth factor. (1GF)

It has been postulated that the growth effects of GH result from somatomedin and other sometimes rather than direct effects of GH on bones and other tissues.

Types: At least 4 somatomedins have been isolated.

Most important one is Insulin-like growth factor- I (IGF – 1).

Another is insulin-like growth factor – II. Higher than normal levels of IGF-1 may increase the risk of several types of cancer.

Deficiency feature: Lack of somatomedin may cause dwarfism in children African pygmies have lack of IGF-1. The liver is thought to be the predominant source of circulating somatomedins.