GROWTH-FACTOR INDUCTION OF NITRIC-OXIDE SYNTHASE IN RAT PHEOCHROMOCYTOMA CELLS

Previous work has suggested that nerve growth factor treatment of PC12 cells induces neuronal nitric oxide synthase, and possibly also endot helial nitric oxide synthase (NOS) and inducible NOS. To further analy ze this process we exposed rat pheochromocytoma (PC12) cells to increa sing concentrations of basic fibroblast growth factor (bFGF), epiderma l growth factor (EGF), nerve growth factor (NGF), and vascular endothe lial cell growth factor (VEGF). Changes in NOS expression were then an alyzed by Western blotting, using antisera generated against the three isoforms of NOS. Our results demonstrate that neuronal NOS was induce d by growth factors that promote both differentiation (bFGF, NGF) and proliferation (EGF). nNOS levels were unaffected by VEGF treatment. In contrast, the levels of endothelial and inducible NOS were undetectab le in these same cells, suggesting that different clonal lines of PC12 cells have different isoform complements. (C) 1997 Elsevier Science B .V.