Nucleon axial-vector form factor in perturbative QCD

We calculate the axial-vector form factor $g_A$($Q^2$) using leading-order perturbative QCD and a variety of distribution amplitudes (wave functions). We learn that $g_A$ falls asymptotically like 1/$Q^4$ and its normalization is determined if we use the same distribution amplitudes that account for the nucleon magnetic form factors. The data on $g_A$ extrapolated to higher $Q^2$ are in accord with the normalization determined in this way.