EPIDERMAL GROWTH-FACTOR INFLUENCES THE NEUROTROPHIC DIFFERENTIATING ACTION OF NERVE GROWTH-FACTOR

Exposure of naive PC12 cells, sympathetic neurons from rat superior ce rvical ganglia, and brain-derived septal neurons to epidermal and nerv e growth factors simultaneously resulted in some alteration of cellula r events induced by nerve growth factor alone. A more pronounced decli ne of catecholamine content, no additional change in acetylcholinester ase activity, and additive stimulation of RNA and protein syntheses we re found in PC12 cells. Earlier elevation of the enzyme activity was o bserved in sympathetic but not in septal neurons. Epidermal growth fac tor appeared to support independently the same level of acetylcholines terase activity in septal neurons as revealed for nerve growth factor during the first week and cell survival throughout 2 weeks of observat ion. The data obtained indicate that epidermal growth factor augments temporarily some effects of nerve growth factor, thus supporting the i dea of an important role of mitogenic growth factors in neural develop ment as complementary and/or substitutive regulators of nerve cell dif ferentiation and survival.