Insulinlike growth factor-1 IGF

Receptors for EGF, insulin, insulinlike growth factor-1 (IGF-1) Receptors for NGF, TGF... 

The receptor for insulinlike growth factor-1 (IGF-1) is also similar to the insulin receptor in structure and tyrosine kinase activity. Thus, in this case it is likely that the hormones (insulin and IGF-1) and their receptors have each evolved from common ancestral genes by duplication and divergence. 

Insulin-dependent diabetes mellitus (IDDM) is an example of a metabolic disease under active consideration for inducible gene therapy strategies. In this disorder, inflammatory cytokines have been shown to activate apoptosis in pancreatic beta cells. Experimental studies indicate that expression of insulinlike growth factor-1 (IGF-1) can prevent the cytokine-mediated destruction of beta cells of the pancreas (Giannoukakis et al., 2001). Regulated expression of IGF-1 in human pancreatic islets, to preserve beta cell function, may be a useful approach in the treatment of certain types of diabetes (Demeterco and Levine, 2001). 

TRH = thyrotropin regulatory hormone PIF = prolactin inhibitory factor GnRH = gonadotropin regulatory hormone IGF-1 = insulinlike growth factor 1 ACTH = corticotropin GH = growth hormone TSH = thyrotropin Prl = prolactin... 

Akekawatchai, C., Holland, J. D., et al. (2005). Transactivation of CXCR4 by the insulinlike growth factor-1 receptor (IGF-1R) in human MDA-MB-231 breast cancer epithelial cells. J Biol Chem 280(48) 39701-8. Epub 2005 Sep 19. 

Somatomedins are polypeptide mediators produced in response to growth hormone in the liver, e.g. insulinlike growth factors (IGFs). In particular, IGF-1 is the main mediator of growth hormone action. 

As indicated in the discussion of axotomy models, the beneficial influences of trophic factors on motor neurons provide potential therapeutic opportunities. Although previous human trials have been disappointing (for review see [111,112]), adenoassociated viral (AAv) delivery of insulinlike growth factor (IGF)-l to muscle prolongs survival in mutant SOD1 mice [111]. Thus, following intramuscular injection, the retrograde transport of AAV-IGF-1 appears to provide trophic influences to motor neurons. 

The neuroprotective effects of other compounds have also been demonstrated to be enhanced when combined with hypothermia. Guan et al. (6) evaluated the efficacy of hypothermia in combination with insulinlike growth factor (IGF) using a modified Levine hypoxic-ischemic model (right carotid ligation plus 10 min of hypoxia in neonatal animals). In this study, the use of hypothermia resulted in a significant extension of the therapeutic time window. Recovery in a cool vs a warm environment (23 C vs 31 C) extended the effectiveness of IGF-1 by up to 4 h. 

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