Neuropeptide Y gene expression in immortalized rat hippocampal and pheochromocytoma-12 cell lines

Employing clonal cell lines derived from rat embryonic hippocampal cells, we detected neuropeptide Y (NPY) mRNA in three progenitor subcloned cell lines. These cell lines upon differentiation express markers indicative of commitment to either neuronal (H19-7; NF +, GFAP -), glial (H19-5; GFAP +, NF -), or bipotential (H583-5; NF +, GFAP + ) lineages. Induction of differentiation was associated with the persistence of the NPY mRNA, however, in the differentiated H19-7 cells a 20-fold increase in NPY mRNA levels was observed (P<0.05). NPY immunoreactivity was observed only in cells with a differentiated neuronal phenotype. The cellular radioimmunoassayable NPY peptide levels increased twelve-fold without a change in extracellular NPY peptide levels by multi-factorially induced neuronal or glial cell differentiation. The differentiated H19-5 cells expressed lower levels of NPY that could not be immunocytochemically detected. The peripheral sympathetic PC-12 neuronal cells examined in the undifferentiated and nerve growth factor-driven differentiated states expressed NPY only upon differentiation. We conclude that NPY is expressed by the cultured undifferentiated and differentiated rat hippocampal clonal cell lines, while the peripheral sympathetic PC-12 neuronal cell line only expresses the NPY gene upon differentiation. These immortalized embryonic neural cell line(s) will provide a hippocampal cell line(s) to conduct future in-vitro investigations targeted at determining the cellular and molecular mechanisms governing NPY gene expression.