Transplantation of cells derived from embryonic stem cells is currently under investigation as a promising strategy to restore functional deficits in neurodegenerative diseases, e.g. Parkinson's disease. To generate cells suitable for transplantation, a neuronal progenitor cell line (ST14A) was derived from embryonic day 14 rat striatum by stable retroviral transfection of the temperature-sensitive SV40 large T antigen and genetically modified by transfection with constructs of the neurotrophic factors ciliary neurotrophic factor (CNTF) [CNTF-ST14A] and glial cell line-derived neurotrophic factor (GDNF) [GDNF-ST14A], respectively. In order to investigate the capacity of these cells to regulate neuronal growth and physiological differentiation, e.g. remodeling of axons and synaptogenesis, we analyzed the expression of molecules which control the cell fate during embryonic development. For the first time, we found endogenous Wnt-5a, a regulator molecule that can induce dopaminergic phenotype, by RT-PCR, Western blot and flow cytometry in the neuronal progenitor cell line ST14A and its derivatives CNTF-ST14A and GDNF-ST14A. The protein was transiently upregulated at the differentiation-inducing non-permissive temperature of 39 degrees C and it was also secreted into the culture medium. Our findings are based on in vitro investigation of artificially immortalized cell lines. However, they raise the possibility that neuronal progenitor cells that might be used to treat neurodegenerative diseases express Wnt-5a, thus promoting their potential for dopaminergic differentiation.