Insulin-like growth factor 1 is essential for normal dendritic growth

J Neurosci Res. 2003 Jul 1;73(1):1-9. doi: 10.1002/jnr.10634.


This study evaluated somatic and dendritic growth of neurons in the frontoparietal cortex of Igf1-/- brains. Pyramidal neuron density was increased by approximately 25% (P =.005) and soma size reduced by approximately 10% (P <.001). Golgi staining revealed that cortical layer II-III neurons exhibited a significant reduction in dendritic length and complexity in Igf1 null mice. Dendritic spine density and presumably synaptic contacts were reduced by 16% (P =.002). Similar findings were obtained for cortical layer V and piriform cortex pyramids. Supporting a reduction in synapses, synaptotagmin levels were reduced by 30% (P <.02) in the Igf1 null brain. Investigation of factors critically involved in dendritic growth and synaptogenesis showed an approximately 50% reduction in cortical CDC42 protein expression (P <.001) and an approximately 10% reduction in brain cholesterol levels (P <.01) in Igf1 null mice. Evidence is presented that Igf1 deletion causes disruptions in lipid and microtubule metabolism, leading to impaired neuronal somatic and dendritic growth. Published 2003 Wiley-Liss, Inc.

MeSH terms

  • Animals
  • Cell Count
  • Cell Division
  • Cell Size / physiology
  • Cholesterol / analysis
  • Dendrites / chemistry
  • Dendrites / physiology*
  • Insulin-Like Growth Factor I / genetics*
  • Insulin-Like Growth Factor I / metabolism*
  • Mice
  • Mice, Mutant Strains
  • Neurites / chemistry
  • Neurites / physiology
  • Pyramidal Cells / chemistry
  • Pyramidal Cells / cytology
  • Pyramidal Cells / ultrastructure
  • Silver Staining
  • Synapses / physiology


  • Insulin-Like Growth Factor I
  • Cholesterol