IGF And The Brain
Being a rather large peptide, there’s question on the blood/brain barrier but
this study shows another beneficial effect of IGF.
Pharmacol. 2004 Apr 19;490(1-3):25-31.
Signaling by insulin-like growth factor 1 in brain.
Bondy CA, Cheng CM.
Developmental Endocrinology Branch, Bldg. 10/10N262, 10 Center Dr, NICHD, NIH,
Bethesda, MD 20892, USA.
The homologous insulin and insulin-like growth factor (IGF) receptors are both
expressed in the brain, in overlapping but distinct neuroanatomical patterns.
In contrast to insulin, IGF1 is also highly expressed within the brain and is
essential for normal brain development. IGF1 promotes projection neuron growth,
dendritic arborization and synaptogenesis. IGF1 acts in an autocrine and/or
paracrine manner to promote glucose utilization, using phosphatidylinositol 3
kinase (PI3K)/Akt, also known as protein kinase B (PKB)/glycogen synthase
kinase 3beta (GSK3beta) pathways similar to insulin signaling in peripheral
tissues. IGF1 promotes neuronal survival during normal brain development mainly
in hippocampal and olfactory systems that depend on postnatal neurogenesis.
IGF1′s anabolic and neuroprotective roles may be coordinated by inhibition of
GSK3beta. The identification of GSK3beta as a major target of brain IGF1
signaling provides a unifying pathway for IGF1′s well-established anabolic and
anti-apoptotic functions, with IGF1-induced inhibition of GSK3beta triggering
multifaceted anabolic and neuroprotective effects.