Testosterone–BSA modifies the transcription of EPOR, through a direct effect on its promoter. Two constructs of the EPOR promoter were made: a short one containing the −188 to −18 sequence‐traditional promoter, termed short promoter, and a second, long promoter, construct containing the −709 to −18bp of the putative promoter region, linked to luciferase. A. Effect of Testosterone–BSA (Testo‐BSA, 10−7M, 24h) on the short and the long promoter constructs, in transiently transfected T47D cells. B. Effect of signaling pathways inhibitors (SB203580: p38 MAPK inhibitor; Wortmannin: PI3K/Akt inhibitor; AG490: JAK2 inhibitor; SP600125: Jnk inhibitor) on the transcriptional activity of Testosterone–BSA (10−7M, 24h) on EPOR short and long promoter constructs.