The levels of Akt1 and Akt2. Western blot for Akt1 and Akt2 in wild type (WT) mammary tissues from four different mice and mammary tumors from four different MTB-IGFIR transgenic mice. Akt3 was evaluated but could not be detected in any of the samples. The WT tissue was taken from adult mice that had not been exposed to doxycycline. β-actin served as a loading control.