4-Aza-5alpha-androstanone(1alpha) and 4-aza-5beta-androstanone(1beta) were synthesized in order to obtain the NMR shielding parameters for the secondary amine group. A combination of the electric field effect and the anisotropy of the magnetic susceptibility of the C-N bond can successfully reproduce the observed SIS values for these androstanes. Drastic chemical shift change of protons near-by nitrogen atom of ammonium salt was observed and shielding parameter for the secondary ammonium group was also obtained. (C) 2003 Elsevier Ltd. All rights reserved.