  Evolution of the magnetic response function in the triangular-lattice Hubbard
model is studied with interaction strength within a systematic
inverse-degeneracy expansion scheme which incorporates self-energy and vertex
corrections and explicitly preserves the spin-rotation symmetry. It is shown
that at half filling the response function goes through a nearly dispersionless
regime around K for intermediate coupling strength, before undergoing an
inversion at strong coupling, resulting in maximum response at the K point,
consistent with the expected 120^o AF instability. Effects of finite
hole/electron doping on the magnetic response function are also examined.
