Steroid and protein regulators of glial cell proliferation.

Any variation in CNP and GS activity in vitro under the effect of growth factors with different mechanisms of action, may indicate a general process of differentiation in the culture. An increase in the GS activity in early passage glioma may be interpreted as an induction of the differentiating phenotype involving cell transformation into a more astrocytic-like culture. Hence, under the above experimental conditions, dexamethasone and insulin are the two factors with the most potent differentiating effect on rat C6 glioma cell line. Comparative studies with growth regulators using different receptor pathways and mechanisms of action may add valuable data to the current knowledge in the field. The data presented in this chapter show the plasticity of C6 glioma to the differentiating effect of various growth factors, especially insulin and dexamethasone, and confirms C6 glioma cell line as a useful model for studies on glial cell properties and proliferation in vitro.