Induction and maintenance of differentiation of rat lens epithelium by FGF-2, insulin and IGF-1

Exp Eye Res. 1998 Oct;67(4):425-31. doi: 10.1006/exer.1998.0534.


The differentiation of rat lens epithelial cells to fibre cells can be mimicked using lens epithelial explants, which differentiate in vitro when exposed to fibroblast growth factor (FGF). A previous study demonstrated that FGF is required only for initiation of differentiation: once induced by FGF, differentiation can be maintained by insulin (as assessed by following the accumulation of fibre-cell specific crystallins). The aim of this investigation was to determine whether insulin-like growth factor 1 (IGF-1) can also maintain differentiation and to include a cellular analysis of explants undergoing insulin-or IGF-maintained differentiation in vitro. Measurement of the accumulation of alpha-, beta- and gamma-crystallins showed that IGF-1, like insulin, can replace FGF-2 in directing the pulses of alpha-, beta- and gamma-crystallin gene expression once differentiation is initiated by FGF-2. Cells in both the peripheral and the central region of the explants responded. Immunolocalization of alpha, beta- and gamma-crystallins in these explants showed that a 15 min pulse of FGF-2 triggered the differentiation of only a few cells, whereas a 12 hr pulse primed virtually all the cells for differentiation. This indicates that in explants, individual cells differ in the rate at which they can respond to FGF-2.

Publication types

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

MeSH terms

  • Animals
  • Blotting, Western
  • Cell Differentiation / drug effects
  • Crystallins / metabolism
  • Culture Techniques
  • Electrophoresis, Polyacrylamide Gel
  • Fibroblast Growth Factor 2 / pharmacology*
  • Fluorescent Antibody Technique
  • Insulin / pharmacology*
  • Insulin-Like Growth Factor I / pharmacology*
  • Lens, Crystalline / cytology
  • Lens, Crystalline / drug effects*
  • Lens, Crystalline / metabolism
  • Rats
  • Rats, Wistar
  • Time Factors


  • Crystallins
  • Insulin
  • Fibroblast Growth Factor 2
  • Insulin-Like Growth Factor I