Figure 1. Lack of estrous cycle in aP2-Cre/ERα^flox/flox female mice.

Vaginal smear analysis was performed on two month-old ERα^flox/flox and aP2-Cre/ERα^flox/flox mice on a daily basis for 12 days. (A) ERα^flox/flox females cycled, whereas aP2-Cre/ERα^flox/flox mice were in constant estrus, as determined by smears which consisted predominantly of cornified squamous epithelial cells. All graphs are representative and show two individuals out of totally seven analyzed. E, estrus; P, proestrus; M, metestrus; D, diestrus. (B) Serum E2 levels in ERα^flox/flox (n = 6) and aP2-Cre/ERα^flox/flox (n = 10) mice with ages between 10 and 14 weeks. Significance was determined by t tests. Error bars represent SEM, ***P<0.001.