Advanced vaginal opening and persistent cornification in ERαKiss1KO and ERαTac2KO females. Average age at vaginal opening of littermate controls and ERαKiss1KO females (A) and ERαTac2KO females (B). Numbers in parentheses above each bar denote the n for each measurement. Representative vaginal cytology over time for control and ERαKiss1KO females (C) and control and ERαTac2KO females (D). Percentage of time spent in diestrus/metestrus and estrus (based on vaginal cytology) from the time of vaginal opening until 8 weeks of age for mice of the indicated genotypes. Numbers in parentheses above each bar denote the n for each measurement. One-way ANOVA, Bonferroni post hoc: ***, P < .001. VO, vaginal opening; C, cornified epithelial cells; N, nucleated epithelial cells; L, leukocytes; D/M, diestrus/metestrus; E, estrus.