Figure 2: The high levels of gonadotropins stimulate E2 biosynthesis but have no effect on follicle growth during the infantile period.

(A) Schematic representation of the procedure used to experimentally decrease FSH levels between 12 and 14 dpn in mice. (B and C) Circulating LH (B) and FSH (C) levels in females treated with saline (−), Ganirelix (+) or Ganirelix plus eCG (eCG). Gonadotropins were simultaneously assayed in the serum from 9 females/group. (D) Circulating E2 levels in 5–6 pooled serum in females treated with saline (−), Ganirelix (+) or Ganirelix plus eCG (eCG), as determined by GC-MS. (E,F) Morphometric analyses of preantral/early antral follicle number (left) and size (right) (E) performed on histological sections of hematoxylin/eosin stained ovarian sections (F) of females treated with saline (−), Ganirelix (+) or Ganirelix plus eCG (eCG) from 3–4 ovaries/group. (G) Schematic view of the superovulation procedure. (H) Effect of the superovulation treatment (eCG/hCG) on circulating E2 levels. (I,J) Effects of the superovulation treatment on follicular growth as shown by fibronectin immunodetection (red) to visualize follicle morphology (I) and morphometric analyses of antral follicle number and size (J) from at least 3 ovaries/group. In F and I, micrographs are representative of the observations performed on 3 ovaries/group. Scale bars: 100 μm. In E and J, morphometric analyses were performed by ImageJ, as described in Materials and Methods.