Resumen
The black hole (BH) mass [M(BH)] is of paramount importance in AGN models, as the dependence of M(BH) on host galaxy properties provides clues to the role of BHs in galaxy formation and evolution. The only direct dynamical method for measuring M(BH) in AGN is the time-consuming reverberation mapping of broad emission lines. Consequently, only for a few AGN M(BH) is known (e.g. Kaspi et al. 2000; Wandel 2002).