Category Archives: Follicles

Immunohistochemical Distribution of Follistatin: DISCUSSION(5)

Similar to follicles, the bovine corpus luteum also displayed stage-specific changes in the follistatin levels. When the corpus luteum was developing but not yet fully functional, immature luteal cells did not display any immuno-staining for follistatin; the amount of staining increased with maturity of the corpus luteum (maximum at mid-dies-trus) and decreased again during regression. Our results are consistent with earlier reports in which expression … Continue reading

Immunohistochemical Distribution of Follistatin: DISCUSSION(4)

Thus, granulosa-derived activin and fol-listatin may have selective paracrine modulatory roles on thecal androgen synthesis and, in turn, affect estradiol production by the granulosa cells. It is not known yet whether higher estradiol production by the granulosa cells caused them to express more follistatin or vice versa. Although existence of a cause-and-effect relationship is speculative at this stage, temporal relationships discovered during this study provide … Continue reading

Immunohistochemical Distribution of Follistatin: DISCUSSION(3)

Relative to follicle wave dynamics, there appears to be a temporal relationship between the expression of follistatin (present study), estradiol production, and morphological features of the dominant and subordinate follicles of cattle. Immediately after divergence in the diameter profiles of dominant and subordinate follicles (i.e., selection of dominant follicle), differential expression of both follistatin (present study) and estradiol production was observed. The granulosa layer of … Continue reading

Immunohistochemical Distribution of Follistatin: DISCUSSION(2)

Follistatin immunostaining was localized only in the granulosa layer of all follicles in the cattle studied, a finding consistent with the results of earlier studies in the rat and human. Follistatin was not detected in the theca interna regardless of follicle type or phase, consistent with an earlier report that theca interna tissues obtained from bovine follicles did not produce follistatin in vitro.

Immunohistochemical Distribution of Follistatin: DISCUSSION(1)

Phase-specific changes in follistatin expression in granulosa and luteal cells documented in the present study are suggestive of a functional role for follistatin in follicular and luteal gland development in cattle. Although follistatin expression was numerically greater in the largest follicle as early as 1 day after wave emergence (i.e., D1W2), the difference among follicles did not reach significance until 3 days after wave emergence … Continue reading

Immunohistochemical Distribution of Follistatin: RESULTS(3)

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 … Continue reading

Immunohistochemical Distribution of Follistatin: RESULTS(2)

A discrete brown-colored granular reaction for follistatin was detected only in the granulosa layer; the theca interna¬†layer was devoid of staining regardless of follicle type or phase. A day effect (p < 0.001) and a follicle effect (p < 0.001) were detected for absorptive index. A decrease in the staining intensity for the dominant follicle over time (Fig. 6) was reflected in a gradual decrease … Continue reading

Immunohistochemical Distribution of Follistatin: RESULTS(1)

The diameter profiles of follicles and corpora lutea are illustrated in Figure 1, and the method for densitometric quantitative analysis is illustrated in Figure 2. The specificity of the immunohistochemical staining was confirmed by adsorbing primary antiserum with excess of follistatin and by omitting the secondary antibody treatment during the staining procedure (Fig. 3). A positive reaction (brown staining) detected after primary antiserum treatment of … Continue reading

Immunohistochemical Distribution of Follistatin: MATERIALS AND METHODS(9)

Similarly, the gray-scale standard deviation values for the positive reaction were converted to a scale of 0-100 and were defined as heterogeneity. Intra- and interday coefficients of variation for gray-scale densitometry were 6.8% and 8.5%, respectively. Used in this fashion, the absorptive index is an indicator of the amount (concentration) of follistatin in the tissue but is independent of the pattern of distribution of follistatin … Continue reading

Immunohistochemical Distribution of Follistatin: MATERIALS AND METHODS(8)

Mean gray-scale values were used to calculate the absorptive index, and standard deviation values were used to calculate heterogeneity. Values were recorded at 4 different locations within the same section that exhibited the positive reaction (corpus luteum or granulosa layer of follicles). Values were also taken from another 4 locations from the same section that exhibited no specific reaction (ovarian stroma for corpus luteum, theca … Continue reading