Fig 2. Systemic estradiol application drives genital cortex growth and advances puberty.

(A) Upper panel: Control rats received daily subcutaneous injection of sesame oil for 5 days (postnatal day [P]26–P30). Lower panel: Outline of a somatosensory cortex (S1) map from the brain of a P30 female treated only with oil. The genital cortex is labeled in black. (B) Same as (A), but prepubescent rats were injected with sesame oil containing estradiol. (C) Absolute area of the clitoris representation in hemispheres of P30 females, which received daily injections (over 5 days) of either sesame oil alone or sesame oil containing estradiol. The genital cortex appears bigger in the estradiol group. (D) Same as (C), but the fraction of genital cortex of the entire S1 is plotted. (E) Absolute area of S1 in hemispheres of animals that received either daily oil or estradiol injections. There is no difference between the 2 groups. (F) Pictures of clitoris and vagina, before and after sesame oil treatment. Note that the vagina stays closed at P30 when animals were injected with sesame oil alone. (G) Same as (F), but for the vagina of estradiol treated animals. The vagina is already open at P30 (lower picture). (H) Mean scores for vaginal opening. A score of 0 represents a closed vagina, whereas a score of 1 stands for an opened vagina. The intermediate state (between open and closed vagina) has a score of 0.5. The vagina stayed closed in almost all control animals (treated with oil) whereas the majority of estradiol animals, showed an open vagina at P30. Each dot represents the score of vaginal opening for one animal. (I) Uterus weights of oil and estradiol treated animals. The uterus in estradiol treated animals is heavier, although this difference was not significant. Each dot represents the uterus weight from one animal. See also S3 Fig and S1 Data.