Left panel: Example of a Western blot: ProNGF is detected in human GCs (cells cultured for 2 and 3 days are shown); middle panel: Control blot, in which pre-adsorbed anti-proNGF antiserum was used; right panel: Example of a Western blot, in which an antiserum to NGF was used. Note that this antiserum, as expected, recognizes both NGF and proNGF and that the GCs shown contain abundant proNGF, while NGF was much less abundant.