Nerve growth factor-mediated induction of tyrosine hydroxylase in a clonal pheochromocytoma cell line

We have established a clonal cell line, PC-G2, from an experimentally induced rat pheochromocytoma. Administration of nerve growth factor to PC-G2 causes a 4- to 8-fold induction in the specific activity of tyrosine hydroxylase [tyrosine 3-monooxygenase; L-tyrosine,tetrahydropteridine:oxygen oxidoreductase(3-hydroxylating); EC 1.14.16.2]. The response is elicited in a dose-dependent fashion, at concentrations above 0.1 microgram/ml. Antiserum to nerve growth factor inhibited the induction of tyrosine hydroxylase. Dexamethasone enhances the nerve growth factor-mediated elevation of tyrosine hydroxylase. After 3--4 days of exposure to nerve growth factor the maximal induction of tyrosine hydroxylase is seen, although a significant increase can be observed after 24 hr. In contrast to the PC-12 cell line (derived from the same tumor), in which neurite outgrowth occurs in response to nerve growth factor, there is no morphological change or alteration in growth rate of PC-G2 cells after exposure to nerve growth factor.