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Showing 1 to 20 of 20 for “"luteolysis"”.
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Induction of the oxytocin receptor and its role in luteolysis in sheep
… (PGF$\sb{2\alpha}$) during spontaneous luteolysis. Continuous treatment with progesterone for 9 or 12 days reduced the density of oxytocin receptors in endometrium and myometrium when compared to the vehicle-treated groups. In the endometrium, withdrawal of progesterone after day 9 …
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Lutalyse® induces uterine-ovarian PGF₂α release in sheep: a critical component of induced luteolysis
… responses to PGF<sub>2α</sub>-induced luteolysis are not known. This study (Exp. 1 and 2) was conducted to determine several pharmacokinetic responses to two dosing regimens of Lutalyse® (PGF<sub>2α</sub>). Experiment 1 was a 2 x 2 factorial design, with Lutalyse and H/Ox as main …
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Role of estradiol and progesterone in regulating prostaglandin F(2 alpha) secretion and luteolysis in the ewe
… F$\sb{2\alpha}$ (PGF$\sb{2\alpha}$) during luteolysis in the ewe. For the first two studies, fifty mixed-breed ewes underwent selective irradiation of both ovaries on day 8 of the cycle to destroy the estrogen-secreting follicles. Twenty ewes were randomly assigned to four treatment groups …
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The Mechanism of Action of Exogenous PGF2alpha in Clearance of Nonspecific Uterine Infections in Sheep and Pigs
… during the luteal phase in sheep causes luteolysis; therefore, it impossible to evaluate the effects of Lutalyse independently of luteolysis. In order to cause an endogenous release of PGF2alpha without causing luteolysis in sheep a PGF2alpha secretagogue (oxytocin) was used in Exp. 5. …
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Regulation of Antepartum Relaxin Release in the Pregnant Rat: Role of the Maternal Pituitary Gland, Luteinizing Hormone and Prostaglandins
… understood, but may be related to functional luteolysis (Endocrinology 107:671, 1980). Factors which served as a beginning for the investigation of the regulation of antepartum relaxin release were those which have been implicated in luteolysis; these are the maternal pituitary, luteinizing …
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Comparison of Luteolysis and Timed Artificial Insemination Pregnancy Rates after Administration of PGF2a in the Muscle or the Ischiorectal Fossa in Cattle
… curves for each heifer were plotted to determine luteolysis. The median times to luteolysis for neck and IRF injections were 18.1 hrs and 20.0 hrs, respectively (p=0.06). Angus cross commercial beef cows (n=1471) at least 30 days post-partum were blocked by age and randomly assigned to be injected …
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Relationships among progesterone, estradiol-17β, 13, 14-dihydro-15-keto-prostaglandin F₂α and prostaglandin F₂α in intact ewes around the time of luteolysis
… the question: Do MPA-containing pessaries delay luteolysis in intact ewes? Ewes were treated with MPA containing (n=10) or blank pessaries (controls; n=8) from d 7 and until d 18 of the estrous cycle for control and until d 22 for MPA-treated ewes; d 0 was the day of estrus. Blood samples were …
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Evaluation of the 5-day vs. 7-day Co-Synch + CIDR protocol in dairy heifers using timed AI.
… a CL (progesterone ≥1 ng/mL) on d 7, and whether luteolysis occurred in 7D heifers. Blood progesterone concentration from d 0 and 3 determined if luteolysis occurred in all heifers. Ovarian structure maps on d 5 and 0 were used to determine ovulation in response to GnRH on d 5. Pregnancy was …
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Regulation of ovarian oxytocin and prostaglandin F2[alpha] release in the ovine oestrous cycle
… in the ovine oestrous cycle, their role in luteolysis and a possible mechanism by which the oxytocin secretory pathway is controlled in ovarian tissue.
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Effect of 6α-methyl-17α hydroxyprogesterone acetate on uterine secretion of prostaglandin (PG) F₂α and luteal sensitivity to exogenous PGF₂α
… of PGF₂α, but it does not interfere with luteolysis. The mechanism by which MPA suppresses PGF₂α and permits luteal regression remains to be determined. Three experiments were conducted to determine whether MPA reduces PGF₂α in uteroovarian blood, causes the release of PGF₂α before d 14 of …
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Angiogenesis and angioregression gene expression analyses in swine corpus luteum
… and angioregression during the CL formation and luteolysis is the isopeptide Endothelin-1 (ET-1), which is well-known to be a potent vasoconstrictor and mitogen for endothelial cells. The goal of the present thesis was to study the role and regulation of vascularisation in an adult vascular bed. …
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Increasing estrus expression in lactating dairy cows
… that: (1) altering progesterone before inducing luteolysis or (2) exposing cows to estradiol cypionate (ECP) or testosterone propionate (TP) after luteolysis would increase occurrence and intensity of estrus. In experiment 1, cows (n = 154) were fitted with an AMS collar and a pressure-sensitive, …
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The effectiveness and efficiency of ovulation induction agents in mares
… control (untreated cycle), a natural cycle with luteolysis induced with prostaglandin F2 alpha (PGF2α), a cycle with ovulation induced with Ovuplant™, and a final cycle with ovulation induced with Ovuplant™ and luteolysis induced with prostaglandinF2alpha (PGF2α). Progesterone levels for …
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Untersuchen zur Regulation der uterinen und ovariellen Durchblutung sowie der Expression von Stickstoffmonoxidsynthasen und Östrogenrezeptoren im Verlauf des Zyklus und der Frühgravidität bei der Stute
… were taken in each case before induction of luteolysis, 12 and 36 hours after that, before injection of hCG and immediately after ovulation. During the further two cycles the mares were treated orally with the NO donor ISDN (ISDN 40â, 30 mg, twice a day). Investigations were carried out on …
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Effects of Preovulatory Estradiol Concentration on Embryo Survival and Pregnancy Establishment in Beef Cows
… exogenous hormones to mimic the luteal phase and luteolysis and then received either estradiol cypionate (ECP), estradiol benzoate (EB) or no treatment (CON) according to Latin Square assignment to mimic a preovulatory period. Ovulation was simulated with an injection of gonadotropin releasing …
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Presynchronizing injections of prostaglandin F[subscript]2alpha[subscript] or prostaglandin F[subscript]2alpha[ subscript + Gonadotropin-releasing hormone before a fixed time artificial insemination CO-Synch + CIDR program in suckled beef cows
… more (P < 0.05) likely than controls to have luteolysis after initial PG injections and reduced (P < 0.05) serum progesterone. In both experiments, pregnancy rates at d 35 did not differ between treatment and control; however, cows classified as anestrous before d -10, but with elevated …
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Embryo Production by Superovulation and Dual Siring in Alpacas
… cloprostenol (187 µg, IM, twice) to induce luteolysis. Receptive females were bred to proven fertile males, once in the AM by one male and once in the evening by the other male and received hCG or GnRH at time of the first breeding. Embryo collections were performed 8 to 9 days after …
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Advanced Studies in Veterinary Anatomy: Angiogenesis in Caprine Reproductive Organs of Non-Pregnant and Pregnant Normal and Swainsonine-Treated Does
… utero-ovarian pathway for the corpus luteum (CL) luteolysis at the end of non-fertile estrous cycle. During pregnancy, this arterio-venous arrangement may transfer luteotropic substances from uterus to ovary, which may serve in maternal recognition of pregnancy and fit the fact that the goat is CL …
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Determining the role of nerve growth factor-beta in seminal plasma on bovine reproduction
… maternal recognition of pregnancy. As a result, luteolysis and embryonic loss will occur. There is, therefore, a need to uncover novel techniques that will minimize these potential losses in cattle. Increasing evidence is available to suggest that seminal plasma proteins play an important role in …