Search Results - "Karsch, Fred J."

Cortisol Reduces Gonadotropin-Releasing Hormone Pulse Frequency in Follicular Phase Ewes: Influence of Ovarian Steroids by Oakley, Amy E, Breen, Kellie M, Clarke, Iain J, Karsch, Fred J, Wagenmaker, Elizabeth R, Tilbrook, Alan J

“…Stress-like elevations in plasma glucocorticoids suppress gonadotropin secretion and can disrupt ovarian cyclicity. In sheep, cortisol acts at the pituitary to…”
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Does Cortisol Inhibit Pulsatile Luteinizing Hormone Secretion at the Hypothalamic or Pituitary Level? by Breen, Kellie M, Karsch, Fred J

“…Elevations in glucocorticoids suppress pulsatile LH secretion in sheep, but the neuroendocrine sites and mechanisms of this disruption remain unclear. Here, we…”
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Psychosocial Stress Inhibits Amplitude of Gonadotropin-Releasing Hormone Pulses Independent of Cortisol Action on the Type II Glucocorticoid Receptor by Wagenmaker, Elizabeth R, Breen, Kellie M, Oakley, Amy E, Tilbrook, Alan J, Karsch, Fred J

“…Our laboratory has developed a paradigm of psychosocial stress (sequential layering of isolation, blindfold, and predator cues) that robustly elevates cortisol…”
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Endocrine Basis for Disruptive Effects of Cortisol on Preovulatory Events by Breen, Kellie M, Billings, Heather J, Wagenmaker, Elizabeth R, Wessinger, Emily W, Karsch, Fred J

“…Stress activates the hypothalamo-pituitary-adrenal axis leading to enhanced glucocorticoid secretion and concurrently inhibits gonadotropin secretion and…”
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Developmental Programming: Impact of Prenatal Testosterone Excess on Pre- and Postnatal Gonadotropin Regulation in Sheep by Manikkam, Mohan, Thompson, Robert C, Herkimer, Carol, Welch, Kathleen B, Flak, Jonathan, Karsch, Fred J, Padmanabhan, Vasantha

“…The goal of this study was to explore mechanisms that mediate hypersecretion of LH and progressive loss of cyclicity in female sheep exposed during fetal life…”
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Does Cortisol Acting Via the Type II Glucocorticoid Receptor Mediate Suppression of Pulsatile Luteinizing Hormone Secretion in Response to Psychosocial Stress? by Breen, Kellie M, Oakley, Amy E, Pytiak, Andrew V, Tilbrook, Alan J, Wagenmaker, Elizabeth R, Karsch, Fred J

“…This study assessed the importance of cortisol in mediating inhibition of pulsatile LH secretion in sheep exposed to a psychosocial stress. First, we developed…”
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Cortisol Interferes with the Estradiol-Induced Surge of Luteinizing Hormone in the Ewe by Wagenmaker, Elizabeth R, Breen, Kellie M, Oakley, Amy E, Pierce, Bree N, Tilbrook, Alan J, Turner, Anne I, Karsch, Fred J

“…Two experiments were conducted to test the hypothesis that cortisol interferes with the positive feedback action of estradiol that induces the luteinizing…”
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Regulation of the gonadotropin‐releasing hormone neuron during stress by McCosh, Richard B., O'Bryne, Kevin T., Karsch, Fred J., Breen, Kellie M.

“…The effect of stress on reproduction and gonadal function has captivated investigators for almost 100 years. Following the identification of…”
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Mechanisms for ovarian cycle disruption by immune/inflammatory stress by Karsch, Fred J, Battaglia, Deborah F, Breen, Kellie M, Debus, Nathalie, Harris, Thomas G

“…This review summarizes highlights of our experiments investigating mechanisms, mediators and sites by which endotoxin disrupts reproductive neuroendocrine…”
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Does Cortisol Mediate Endotoxin-Induced Inhibition of Pulsatile Luteinizing Hormone and Gonadotropin-Releasing Hormone Secretion? by Debus, Nathalie, Breen, Kellie M, Barrell, Graham K, Billings, Heather J, Brown, Martha, Young, Elizabeth A, Karsch, Fred J

“…Bacterial endotoxin (lipopolysaccharide), a commonly used model of immune/inflammatory stress, inhibits reproductive neuroendocrine activity and concurrently…”
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Membrane-initiated actions of estradiol (E2) in the regulation of LH secretion in ovariectomized (OVX) ewes by Arreguin-Arevalo, J Alejandro, Ashley, Ryan L, Wagenmaker, Elizabeth R, Oakley, Amy E, Karsch, Fred J, Nett, Terry M

“…We demonstrated that E2 conjugated to BSA (E2BSA) induces a rapid membrane-initiated inhibition of LH secretion followed hours later by a slight increase in LH…”
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Does the Type II Glucocorticoid Receptor Mediate Cortisol-Induced Suppression in Pituitary Responsiveness to Gonadotropin-Releasing Hormone? by Breen, Kellie M, Stackpole, Catherine A, Clarke, Iain J, Pytiak, Andrew V, Tilbrook, Alan J, Wagenmaker, Elizabeth R, Young, Elizabeth A, Karsch, Fred J

“…Stress-like elevations in plasma cortisol suppress LH pulse amplitude in ovariectomized ewes by inhibiting pituitary responsiveness to GnRH. Here we sought to…”
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Does Season Alter Responsiveness of the Reproductive Neuroendocrine Axis to the Suppressive Actions of Cortisol in Ovariectomized Ewes? by BREEN, Kellie M, KARSCH, Fred J

“…Season can profoundly influence activity of the hypothalamic-pituitary-adrenal axis and alter reproductive neuroendocrine responsiveness to stress and gonadal…”
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Endotoxin Inhibits the Surge Secretion of Gonadotropin-Releasing Hormone via a Prostaglandin-Independent Pathway by Breen, Kellie M, Billings, Heather J, Debus, Nathalie, Karsch, Fred J

“…Immune/inflammatory challenges, such as bacterial endotoxin, disrupt gonadotropin secretion and ovarian cyclicity. We previously determined that endotoxin can…”
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New insights regarding glucocorticoids, stress and gonadotropin suppression by Breen, Kellie M., Karsch, Fred J.

“…This review highlights our recent work investigating the inhibitory effects of acute, physiologic stress-like increases in cortisol on reproductive…”
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Developmental Programming: Impact of Prenatal Testosterone Excess on Pre- and Postnatal Gonadotropin Regulation in Sheep1 by Manikkam, Mohan, Thompson, Robert C, Herkimer, Carol, Welch, Kathleen B, Flak, Jonathan, Karsch, Fred J, Padmanabhan, Vasantha

“…The goal of this study was to explore mechanisms that mediate hypersecretion of LH and progressive loss of cyclicity in female sheep exposed during fetal life…”
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Neuroendocrine Control of FSH Secretion: IV. Hypothalamic Control of Pituitary FSH-Regulatory Proteins and Their Relationship to Changes in FSH Synthesis and Secretion by SHARMA, Tejinder P, NETT, Terry M, KARSCH, Fred J, PHILLIPS, David J, LEE, James S, HERKIMER, Carol, PADMANABHAN, Vasantha

“…The current dogma is that the differential regulation of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) synthesis and secretion is modulated…”
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Changes in the 5-HT2A receptor system in the pre-mammillary hypothalamus of the ewe are related to regulation of LH pulsatile secretion by an endogenous circannual rhythm by Chemineau, Philippe, Daveau, Agnès, Pelletier, Jean, Malpaux, Benoît, Karsch, Fred J, Viguié, Catherine

“…We wanted to determine if changes in the expression of serotonin 2A receptor (5HT2A receptor) gene in the premammillary hypothalamus are associated with…”
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Neuroendocrine Control of Follicle-Stimulating Hormone (FSH) Secretion: II. Is Follistatin-Induced Suppression of FSH Secretion Mediated via Changes in Activin Availability and Does It Involve Changes in Gonadotropin-Releasing Hormone Secretion? by PADMANABHAN, Vasantha, BATTAGLIA, Deborah, BROWN, Morton B, KARSCH, Fred J, LEE, James S, PAN, Wenqin, PHILLIPS, David J, VAN CLEEFF, Judith

“…The objective of the present study was to determine to what extent activin participates in setting the level of FSH secretion and if this regulation includes…”
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Morphological Plasticity in the Neural Circuitry Responsible for Seasonal Breeding in the Ewe by Adams, Van L, Goodman, Robert L, Salm, A. K, Coolen, Lique M, Karsch, Fred J, Lehman, Michael N

“…An increase in the response of GnRH neurons to estrogen negative feedback is responsible for seasonal anestrus in the ewe, but the underlying neural mechanisms…”
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