  We calculate the isovector response function of hot nuclear matter using
various effective Skyrme interactions. For Skyrme forces with a small effective
mass the strength distribution is found to be nearly independent of
temperature, and shows little collective effects. In contrast effective forces
with an effective mass close to unity produce sizeable collective effects at
zero temperature which disappear at temperatures of a few MeV. We discuss the
relevance of these results for the saturation of the multiplicity of photons
emitted by the giant dipole resonance in hot nuclei beyond $T$=3 MeV observed
in recent experiments.
