This study sought to characterize the rapid intraovarian mRNA response of key folliculogenic factors that may contribute to the restoration of folliculogenesis during 2-10 days of photostimulation in Siberian hamsters. Adult hamsters were exposed to short photoperiod (8L:16D) for 14 weeks (SD). A subset were then transferred to long photoperiod (16L:8D) for 2 (PT day-2), 4 (PT day-4), or 10 days (PT day-10). Quantitative real-time PCR was used to measure intraovarian mRNA expression of: gonadotropin releasing hormone (GnRH), follicle stimulating hormone β-subunit (FSHβ-subunit), luteinizing hormone β-subunit (LHβ-subunit), FSH and LH receptors, estrogen receptors α and β (Esr1 and Esr2), matrix metalloproteinase (MMP)-2 and -9, anti-Müllerian hormone (AMH), inhibin-α subunit, fibroblast growth factor-2 (FGF-2) and proliferating cell nuclear antigen (PCNA). Compared to SD, plasma FSH concentrations increased on PT day-4 and the number of antral follicles and corpora lutea increased on PT day-10. FSHR and inhibin-α mRNA expression also increased on PT day-4, whereas LHR and proliferation marker PCNA both increased on PT day-10 as compared to SD. Esr1 mRNA increased on PT day-2 and remained significantly increased as compared to SD, whereas Esr1 mRNA increased only on PT day-2, similar to FGF-2 and MMP-2 results. No differences were observed in mRNA expression in ovarian GnRH, FSHβ- and LHβ-subunits, AMH, and MMP-9 mRNA with 2-10 days of photostimulation. Rapid increases in intraovarian FSHR and inhibin-α mRNA and antral follicle/corpora lutea numbers suggest that the ovary is primed to react quickly to the FSH released in response to brief periods of photostimulation.
© 2015 Wiley Periodicals, Inc.