17β-(N-tert-butylcarbomoyl)-4-aza-5α-androstane-1-en-3-one is an active site directed slow time-dependent inhibitor of human steroid 5α-reductase 1. - Tian,G.; Stuart,JD.; Moss,ML.; Domanico,PL.; Bramson,HN.; Patel,IR.; Kadwell,SH.; Overton,LK.; Kost,TA.; Mook,RA. (Biochemistry J, 1994)