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Browsing by Author "Niswender, Gordon, advisor"

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    The role of interferon-tau (IFNT) in luteal gene expression, steroidogenesis, and luteal lifespan in the ewe
    (Colorado State University. Libraries, 2009) Bott, Rebecca Clark, author; Bruemmer, Jason, advisor; Niswender, Gordon, advisor
    Interferon-tau (IFNT) was evaluated for endocrine actions on the corpus luteum (CL). The hypothesis was that infusion of IFNT would increase luteal expression of interferon-stimulated gene (ISG)-15, and the length of time for ewes to return to estrus. Osmotic pumps containing 200 μg IFNT or BSA (n=12 each) were connected to the uterine vein of non-pregnant ewes 10 days post-estrus. Messenger RNA encoding ISG15 was elevated in CL from pregnant and IFNT-infused ewes (P<0.05) compared to nonpregnant and BSA-treated ewes, respectively. Luteal mRNA encoding ISG15 from ewes treated with IFNT was greater than in ewes treated with BSA (P<0.05). Serum concentrations of progesterone were not different in ewes that received infusions of BSA or IFNT. Progesterone decreased by six hours (P<0.05) in ewes that received BSA+PGF or IFNT+PGF, but did not differ in ewes that received infusions of IFNT +/- PGF at 8, 10, or 12 hours after PGF. There were no differences in prostaglandin E synthase (PGES) or prostaglandin F synthase (PGFS), or in prostaglandin dehydrogenase (PGDH), steroidogenic acute regulatory protein (StAR), peripheral type benzodiazepine receptor (PBR), cytochrome P450 side chain cleavage enzyme (CYP-11A), or 3μ-hydroxysteroid dehydrogenase (3μ-HSD). Seven day infusion of IFNT during the time frame of maternal recognition of pregnancy resulted in 20% of IFNT-treated ewes returning to estrus by d19 compared to 100% of BSA-treated ewes (P<0.01). In conclusion IFNT acts systemically, alters gene expression in the corpus luteum, and decreases the number of ewes returning to estrus by d19.