  We propose an interpolating formula for the amplitude induced by the axial
anomaly, concentrating on the $\pi^0\gamma^{\ast}\gamma^{\ast}$ transition form
factor. The QCD corrections to this amplitude are generally described by two
major contributions coming from the $q\bar{q}$ bound state and the background
continuous spectrum, respectively.
  For the first contribution, we include the lowest vector bound state using
the realization of the dynamical gauge boson of hidden local symmetry. The
second contribution is included as the triangle quark loop in which a
constituent mass is adopted as a internal quark mass and the amplitudes are
smeared out around the threshold. Using the resulting form factor, we fit the
experimental data for the $\pi^0\gamma$ and the $\omega\pi^0$ transition form
factors and show that our result describes the experimental data well.
