Presentation Title

Photostimulation of regressed ovaries increases desert hedgehog (Dhh) and Indian hedgehog (Ihh) mRNA expression in Siberian hamsters

Faculty Mentor

Kelly A. Young

Start Date

17-11-2018 8:30 AM

End Date

17-11-2018 10:30 AM

Location

CREVELING 66

Session

POSTER 1

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Follicle stimulating hormone (FSH) is an important component in the regulation of seasonal ovarian function. When female Siberian hamsters (Phodopus sungorus) are exposed to inhibitory short day lengths (SD), plasma FSH is reduced which decreases ovarian function. Reproductive functionality returns in a process called recrudescence when hamsters are exposed to stimulatory long day lengths (LD). While the importance of FSH for recrudescence has been well-studied, little is known about how other ovarian factors contribute to recrudescence. The hedgehog signaling pathway is involved in embryonic differentiation and tissue regeneration and may also play a role in in ovarian folliculogenesis. Both Desert hedgehog (Dhh) and Indian hedgehog (Ihh), key ligands in this pathway, have been localized to mammalian ovaries. Because ovarian recrudescence involves substantial tissue remodeling, we hypothesized that Dhh and Ihh mRNA expression may be involved in the photostimulated return of ovarian function and may be regulated by FSH. To address this hypothesis, ovaries were collected from hamsters (n=60) exposed to 14-weeks of LD (functional) or SD (regressed), or exposed to 14-weeks of SD plus 2 weeks of LD (post-transfer recrudescing groups, PT). The PT groups were exposed to GnRH inhibitor acyline (PTA); acyline +FSH (PTAF), mannitol vehicle alone (PTV), or no treatment (PT) for the two weeks of LD stimulation. Ihh mRNA expression peaked in the PT, PTA, and PTAF groups as compared to expression in both SD and LD. Dhh mRNA expression peaked in the PT group as compared to the SD and PTA ovaries, and PTAF Dhh levels were higher than those in the PTA group. Because Ihh and Dhh peaked in PT groups, the hedgehog signaling pathway may be involved in ovarian recrudescence. However, only Dhh mRNA expression showed differential regulation by FSH, with Dhh mRNA decreasing with reduced FSH.

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Nov 17th, 8:30 AM Nov 17th, 10:30 AM

Photostimulation of regressed ovaries increases desert hedgehog (Dhh) and Indian hedgehog (Ihh) mRNA expression in Siberian hamsters

CREVELING 66

Follicle stimulating hormone (FSH) is an important component in the regulation of seasonal ovarian function. When female Siberian hamsters (Phodopus sungorus) are exposed to inhibitory short day lengths (SD), plasma FSH is reduced which decreases ovarian function. Reproductive functionality returns in a process called recrudescence when hamsters are exposed to stimulatory long day lengths (LD). While the importance of FSH for recrudescence has been well-studied, little is known about how other ovarian factors contribute to recrudescence. The hedgehog signaling pathway is involved in embryonic differentiation and tissue regeneration and may also play a role in in ovarian folliculogenesis. Both Desert hedgehog (Dhh) and Indian hedgehog (Ihh), key ligands in this pathway, have been localized to mammalian ovaries. Because ovarian recrudescence involves substantial tissue remodeling, we hypothesized that Dhh and Ihh mRNA expression may be involved in the photostimulated return of ovarian function and may be regulated by FSH. To address this hypothesis, ovaries were collected from hamsters (n=60) exposed to 14-weeks of LD (functional) or SD (regressed), or exposed to 14-weeks of SD plus 2 weeks of LD (post-transfer recrudescing groups, PT). The PT groups were exposed to GnRH inhibitor acyline (PTA); acyline +FSH (PTAF), mannitol vehicle alone (PTV), or no treatment (PT) for the two weeks of LD stimulation. Ihh mRNA expression peaked in the PT, PTA, and PTAF groups as compared to expression in both SD and LD. Dhh mRNA expression peaked in the PT group as compared to the SD and PTA ovaries, and PTAF Dhh levels were higher than those in the PTA group. Because Ihh and Dhh peaked in PT groups, the hedgehog signaling pathway may be involved in ovarian recrudescence. However, only Dhh mRNA expression showed differential regulation by FSH, with Dhh mRNA decreasing with reduced FSH.