  We revisit the "two-component virial theorem" (2VT) in the light of recent
theoretical and observational results related to the "dark matter"(DM) problem.
This modification of the virial theorem offers a physically meaningful
framework to investigate possible dynamical couplings between the baryonic and
DM components of extragalactic systems. In particular, we examine the
predictions of the 2VT with respect to the "acceleration-discrepancy relation"
(ADR). Considering the combined data (composed of systems supported by rotation
and by velocity dispersion), we find that: (i) the overall behavior of the 2VT
is consistent with the ADR; and (ii) the 2VT predicts a nearly constant
behavior in the lower acceleration regime, as suggested in recent data on dwarf
spheroidals. We also briefly comment on possible differentiations between the
2VT and some modified gravity theories.
