Interestingly, the only difference between mouse and human oocytes in this analysis was the presence of FS mRNA in human but not mouse oocytes. The mouse primers were located identically to the human primers, and the FS gene is highly conserved between species, so this difference is not likely due to differences in PCR sensitivity. Moreover, FS mRNA was detected in mouse embryos as well as in adult ovaries, both of which served as positive controls. FS has been previously demonstrated to bind activin nearly irreversibly and to neutralize activin’s bioactivity. Thus, if the FS mRNA in human oocytes is translated, this difference in FS expression might make human oocytes more resistant to the effects of activin relative to mouse oocytes, or limit the time over which activin can exert its signal. birth control yasmin
Using a highly sensitive, single-oocyte RT-PCR approach, we were unable to detect inhibin/activin subunit mRNA in human or mouse oocytes. Since we meticulously removed all cumulus cells before oocyte extraction, our RT-PCR results should reflect transcripts of oocyte origin as opposed to surrounding tissue. This is critical, since we were able to detect evidence of granulosa cell contamination of oocyte mRNA when as few as 5 granulosa cells remained attached to the oocyte before extraction.