  We consider the thermodynamic behavior of a disordered interacting electron
system in two dimensions. We show that the corrections to the thermodynamic
potential in the weakly localized regime give rise to a non monotonic behavior
of the specific heat both in temperature and magnetic field. From this effect
we predict the appearance of adiabatic hysteresis in the magnetoconductance.
Our results can be interpreted as precursor effect of formation of local
moments in disordered electron systems. We also comment on the relevance of our
analysis in three dimensional systems.
