No differences were detected (p > 0.5) in the absorptive index (Fig. 4) and staining pattern (Fig. 7) among the preselection follicles (D1W2). After selection, the absorptive index was markedly higher (p < 0.05) in the granulosa layer of dominant follicles than in the subordinate follicles (D3W1 and the ovulatory wave). The absorptive index (Fig. 4) and staining pattern (Fig. 7) of dominant follicles of the ovulatory wave were similar to those of the growing dominant follicles of wave 1 (D3W1). In sequence of follicle maturation (both dominant and subordinate), follistatin expression was maximal during the mid-growing phase and decreased progressively through the static and regressing phases. buy flovent inhaler
Follistatin was detected (Fig. 8) in the luteal cells during early diestrus (6 days after ovulation) and mid-diestrus (between 9 to 13 days after ovulation), but not during metes-trus (3 days after ovulation) or proestrus (between 17 to 21 days after ovulation). Not all luteal cells displayed staining for follistatin. Cells exhibiting the positive reaction were present in close proximity to blood capillaries (Fig. 8c, inset). The granular reaction was strongest in the perinuclear part of the luteal cell cytoplasm, and in most cases the reaction was localized more on one side of the nucleus (Fig. 8c, inset). A higher absorptive index (p < 0.05) was detected in mid-diestrus than in all the other stages. The heterogeneity increased progressively (p < 0.05) from metes-trus to mid-diestrus and decreased thereafter (p < 0.05). Regressed corpora lutea from the previous estrous cycle (collected 3-6 days after ovulation) did not display any follistatin reaction.
FIG. 7. Immunohistochemical distribution of follistatin (brown color) in the wall of the preselection follicles of wave 2 (a, largest; b, second largest) and in follicles of the ovulatory wave (c, preovulatory dominant; d, subordinate). The granulosa layers of preselection follicles (a, b) have similar staining intensity, while the preovulatory follicle (c) displays an intense reaction in contrast to its subordinate counterpart (d). Bar = 50 mm.
FIG. 8. Immunohistochemical distribution of follistatin (brown color) in the corpus luteum during metestrus (a), early diestrus (b), mid-diestrus (c), and proestrus (d). Luteal cells stained positively for follistatin only during diestrus (b, c). Note the stronger reaction in the part of cytoplasm facing a blood capillary (inset in c). Bar = 50 mm.