Structure-activity relationship (SAR) analysis of a family of steroids acutely controlling steroidogenesis

► Steroids oxygenated at the 3, 17 and 19 carbons potently inhibit steroid biosynthesis. ► These steroids act through an interaction with the CRAC motif of the TSPO. ► Steroids oxygenated at the 3, 17 and either the 4, 7 or 11 carbons inhibit steroidogenesis at a post-TSPO step. ► Androstenetriol derivatives oxygenated at multiple positions are non-toxic.