Neuropeptide Y (NPY) in PC12 phaeochromocytoma cultures: responses to dexamethasone and nerve growth factor.

High concentrations of a novel regulatory peptide, neuropeptide Y, have been identified within the PC12 rat phaeochromocytoma cell line by radioimmunoassay and chromatographic analysis. The cellular concentration of this peptide has been demonstrated to be predominantly influenced by the presence of nerve growth factor. After 14 days in culture in the presence of dexamethasone, NPY concentrations were 0.19 +/- 0.03 pmol/mg protein, whereas following similar exposure to nerve growth factor, concentrations were 3.44 +/- 0.19 pmol/mg protein. Addition of nerve growth factor to the dexamethasone-treated cells resulted in a rise in NPY concentration to 0.90 +/- 0.08 pmol/mg over 7 days, whereas addition of dexamethasone to the cells treated with nerve growth factor resulted in no further rise in NPY concentration. The concentrations of NPY far exceed those previously reported for neurotensin in PC12 cells, under the same culture conditions. These two peptides appear also to be regulated by different mechanisms.