A comparison of neurotrophic effects of epidermal growth factor and basic fibroblast growth factor in primary cultured neurons from various regions of fetal rat brain.

Effects of recombinant human epidermal growth factor (hEGF) on survival of primary cultured neurons from various regions of fetal rat brain were compared with those of recombinant human basic fibroblast growth factor (hbFGF). Addition of hEGF (0.001-10 ng/ml) in chemically-defined serum-free medium enhanced significantly the survival of cultured neurons from all regions tested, i.e., cerebral cortex, septum, striatum, hippocampus, thalamus, colliculus and cerebellum. However, its effective concentration differed considerably with the regions. The most sensitive regions were the colliculus and cerebellum (minimum effective concentration, 0.001 ng/ml), while the least sensitive was the cerebral cortex (minimum effective concentration, 10 ng/ml). Maximum numbers of surviving neurons in the presence of hEGF were smaller than those of hbFGF in all regions. Maximum effects of hEGF compared with those of hbFGF was greatest in the striatum and smallest in the cerebral cortex. These results suggest that hEGF may exert neurotrophic effects for limited populations of brain neurons. When hEGF (1-10 ng/ml) and hbFGF (0.01-10 ng/ml) were added together, hEGF increased the effects of a lower concentration of hbFGF in an additive manner, but the maximum effects of hbFGF were not potentiated by hEGF in all regions tested. Therefore, mechanisms underlying the effects of hEGF very probably overlap with those of hbFGF.