  We have performed a systematic angle-resolved photoemission study of as-grown
and oxygen-reduced Pr$_{2-x}$Ce$_x$CuO$_4$ and Pr$_{1-x}$LaCe$_{x}$CuO$_4$
electron-doped cuprates. In contrast to the common belief, neither the band
filling nor the band parameters are significantly affected by the oxygen
reduction process. Instead, we show that the main electronic role of the
reduction process is to remove an anisotropic leading edge gap around the Fermi
surface. While the nodal leading edge gap is induced by long-range
antiferomagnetic order, the origin of the antinodal one remains unclear.
