Abstract
To clarify the development of follicular growth and atresia in the immature ovary, rats. ovaries and blood were removed at fixed points during the period from 0 to 35 days after birth (Day 0 to Day 35). The ovaries were immunohistochemically examined, and blood concentrations of serum follicle-stimulating hormone (FSH) and estrogen (E) were measured. We investigated how time-course changes in follicular cell proliferation, estrogen receptor beta (ERbeta), apoptosis, and FSH and E concentrations are connected with follicular growth and atresia. Apoptosis was found in the ova from Day 0 to Day 3. On Day 15, apoptosis occurred in some granulosa cell nuclei in some follicles, but BrdU uptake and the presence of cyclin D2 and ER beta could be observed in other granulosa cells. From Day 17, apoptosis increased in the follicular granulosa cells, and BrdU uptake and the presence of cyclin D2 and ERbeta were decreased. Follicular atresia continued, reaching a peak on Day 30. Serum FSH and E concentrations increased until Day 15, then markedly decreased after Day 17. The mechanism of apoptosis in the ova from Day 0 to 3 has not been clarified. However, the onset of follicular atresia was caused by apoptotic degeneration from Days 15 to 17. These results showed that the oocytes were selected by apoptosis at 2 points in the time-course of the maturation of the ovary.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
