somatomedin

S. A is a peptide (MW about 4,000), synthesized in the liver and probably in the kidney, that is capable of stimulating certain anabolic processes in bone and cartilage, such as synthesis of DNA, RNA, and protein (including chondromucoprotein), and the sulfation of mucopolysaccharides; secretion and/or biological activity of s. is known to be dependent on somatotropin. SEE ALSO: insulinlike growth factor. [somato, tropin + mediator + -in]

* * *

so·ma·to·me·din sō-.mat-ə-'mēd-ən, .sō-mət-ə- n any of several endogenous peptides produced esp. in the liver that are dependent on and prob. mediate growth hormone activity (as in sulfate uptake by epiphyseal cartilage)

* * *

n.

a protein hormone, produced by the liver in response to stimulation by growth hormone, that stimulates protein synthesis and promotes growth. It is biochemically similar to insulin and has some actions similar to insulin; it is therefore sometimes said to have insulin-like activity (ILA) or is referred to as insulin-like growth factor (IGF).

* * *

so·ma·to·me·din (so″mə-to-meґdin) any of several peptides formed in the liver and other tissues and found in plasma, complexed with transport proteins; they stimulate cellular growth and replication, particularly in bone and muscle, as second messengers in the somatotropic actions of growth hormone and also have insulin-like biological activities. Two such peptides have been isolated, insulinlike growth factors I and II (see under factor).