Perinatal ovarian receptivity to estrogens.

<p>A–D: Quantitative RT-PCR for Esr1 (A), Esr2 (B), Gper (C) and Nr1i2 (D) performed on control ovaries at e18.5, day of birth (PND0) and PND12. Each point is constituted by three pools of at least four animals. Data points represent the mean ± SEM of the fold-change in target gene expression relative to a Snx17 reference gene and calibrator sample. Each point represents mRNA from 3 pools of ovaries from 3 animals. *p<0.05 (ANOVA, followed by PLSD test). <b>x</b> shows a statistically significant difference from e18.5 and <b>y</b> shows a statistically significant difference from PND0. E–P. <i>In situ</i> hybridizations for Esr1 (E, H), Esr2 (F, I, K), and Gper (G, J, L) in PND1 (E–G), PND6 (H-K) and PND2 (L-P) control ovaries show lower Esr1 expression in the ovary than in the oviduct epithelium (Ovd), higher expression of Esr2 in granulosa cells with follicle growth, and expression of Gper in the oocytes and granulosa cells. Inset in F shows a higher magnification of a group of follicles boxed in F. K shows a higher magnification of a primary (Iary and a secondary (IIary) follicles boxed in I. Inset in G shows another section of the ovary containing the oviduct. A comparison of <i>Gper</i> mRNA profile by <i>in situ</i> hybridization (L) with Esr2 (N, red) and Ybx2 (M, cytoplasmic, green) (and merged pictures O) by immunofluorescence revealed co-expression of both receptors in oocytes at the time of treatment. P shows hybridization with <i>Gper</i> sense probe. Scale bar: 100 µm except in insert in F and K (50 µm). Q-T. Quantitative RT-PCR for <i>Esr1</i> (Q), <i>Esr2</i> (R), <i>Gper</i> (S) and <i>Nr1i2</i> (T) using ovarian samples of controls (white bars) and animals treated with 10 µg E2 at PND0 (2 h after injection) and PND1 (black bars) shows E2 impairment of post-natal <i>Gper</i> up-regulation. Each bar represents mean ± SEM of the fold-change in target gene expression relative to a Snx17 reference gene and calibrator sample. Each point represents mRNAs from 3 to 6 pools of 6–16 and 10–26 ovaries, respectively. *p<0.05 (ANOVA, followed by PLSD test).