FIG. 3.

Concentrations of intraovarian steroids in AhR^−/− females and the rescue of ovulation by estradiol treatment. (A) Schematic representation of the experimental procedure used to determine intraovarian steroid concentrations during the preovulatory period. (B) Intraovarian estradiol concentrations in AhR^+/+ and AhR^−/− females. The ovaries of at least three AhR^+/+ and three AhR^−/− female mice were collected at the times indicated in panel A. Estradiol concentrations were then determined by liquid chromatography-mass spectrometry analysis. *, P < 0.10; **, P < 0.05. (C) Intraovarian testosterone concentrations were determined as described for panel B. (D) Schematic representation of the experimental estradiol administration procedure used to rescue the ovulation of AhR^−/− mice. Mice treated with PMSG at day 1 were divided into two groups. One group was treated with various quantities of estradiol, while the other group was given vehicle alone on day 2. The mice from both groups were treated with hCG on day 3, and ovulation was assessed at day 4. (E) Effects of estradiol administration on ovulation in AhR^−/− females. After the treatment of AhR^+/+ and AhR^−/− females with PMSG and hCG, the oocytes released by ovulation were counted (open bars). AhR^−/− females were also given an intraperitoneal injection of 5 to 20 ng 17β-estradiol (E2) or vehicle alone (filled bars) as described for panel D prior to counting the ovulated oocytes. *, P < 0.025; **, P < 0.005.