Evidence for an important role of IGF-I and IGF-II for the early development of chick sympathetic neurons

Neuron. 1995 Apr;14(4):731-41. doi: 10.1016/0896-6273(95)90217-1.


The ability of immature neurons from chick lumbosacral sympathetic ganglia to proliferate in vitro was used to identify factors that affect neurogenesis. Under serum-free culture conditions, insulin-like growth factor I (IGF-I), IGF-II, or insulin caused an increase in the proportion of cells that incorporated [3H]thymidine. In addition, IGFs also stimulated neurite outgrowth from these immature sympathetic neurons. IGF-I and IGF-II mRNA was found to be expressed in E7 sympathetic ganglia during the period of neurogenesis. IGF-I was detectable in fibroblasts, whereas IGF-II mRNA was expressed by neurons, glia, and fibroblasts. Elimination of endogenous IGFs by neutralizing antibodies resulted in a reduction of neuron proliferation and neuron number, whereas elevation of IGF levels by treatment with IGF-I increased sympathetic neuron proliferation in vivo. These findings suggest an important role of IGFs for the development of sympathetic neurons and imply a general role of IGFs in the control of neurogenesis and neurite outgrowth.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Cell Count
  • Cell Division*
  • Cells, Cultured
  • Chick Embryo
  • Ganglia, Sympathetic / cytology
  • Ganglia, Sympathetic / metabolism
  • Gene Expression
  • Insulin-Like Growth Factor I / genetics
  • Insulin-Like Growth Factor I / pharmacology*
  • Insulin-Like Growth Factor II / genetics
  • Insulin-Like Growth Factor II / pharmacology*
  • Molecular Sequence Data
  • Neurites / physiology
  • Neurons / cytology*
  • RNA, Messenger / metabolism
  • Sympathetic Nervous System / cytology
  • Sympathetic Nervous System / embryology*


  • RNA, Messenger
  • Insulin-Like Growth Factor I
  • Insulin-Like Growth Factor II