Search Results - "Karsch, F. J."

Psychosocial stress suppresses attractivity, proceptivity and pulsatile LH secretion in the ewe by Pierce, B.N., Hemsworth, P.H., Rivalland, E.T.A., Wagenmaker, E.R., Morrissey, A.D., Papargiris, M.M., Clarke, I.J., Karsch, F.J., Turner, A.I., Tilbrook, A.J.

“…Various stressors suppress pulsatile secretion of luteinizing hormone (LH) in ewes and cortisol has been shown to be a mediator of this effect under various…”
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Estradiol enables cortisol to act directly upon the pituitary to suppress pituitary responsiveness to GnRH in sheep by Pierce, B N, Stackpole, C A, Breen, K M, Clarke, I J, Karsch, F J, Rivalland, E T A, Turner, A I, Caddy, D J, Wagenmaker, E R, Oakley, A E, Tilbrook, A J

“…We have shown that cortisol infusion reduced the luteinizing hormone (LH) response to fixed hourly GnRH injections in ovariectomized ewes treated with…”
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Gonadotropin-releasing hormone requirements for ovulation by Karsch, F.J. (University of Michigan, Ann Arbor, MI.), Bowen, J.M, Caraty, A, Evans, N.P, Moenter, S.M

“…This article addresses the role of GnRH in ovulation in the context of two general models of GnRH action--deterministic and permissive. According to the…”
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Endocrine alterations that underlie endotoxin-induced disruption of the follicular phase in ewes by Battaglia, D.F, Krasa, H.B, Padmanabhan, V, Viguie, C, Karsch, F.J

“…Two experiments were conducted to investigate endocrine mechanisms by which the immune/inflammatory stimulus endotoxin disrupts the follicular phase of the…”
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Estradiol Requirements for Induction and Maintenance of the Gonadotropin-Releasing Hormone Surge: Implications for Neuroendocrine Processing of the Estradiol Signal by Evans, N. P., Dahl, G. E., Padmanabhan, V., Thrun, L. A., Karsch, F. J.

“…Abstract Two experiments were performed to examine the temporal requirements of the estradiol signal for the GnRH and LH surges in the ewe. Hypophyseal portal…”
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Photoperiodic synchronization of a circannual reproductive rhythm in sheep: identification of season-specific time cues by WOODFILL, C. J. I, WAYNE, N. L, MOENTER, S. M, KARSCH, F. J

“…Seasonal reproduction in the ewe is generated by an endogenous circannual rhythm of reproductive neuroendocrine activity. Exposure to as few as 70 days of…”
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Seasonal changes in gonadotropin-releasing hormone secretion in the ewe: alteration in response to the negative feedback action of estradiol by Karsch, F.J, Dahl, G.E, Evans, N.P, Manning, J.M, Mayfield, K.P, Moenter, S.M, Foster, D.L

“…Two experiments were performed to test the hypothesis that there is a seasonal change in the negative feedback effect of estradiol on episodic secretion of…”
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Hypothalamic, pituitary and gonadal regulation of FSH by Padmanabhan, V, Karsch, F J, Lee, J S

“…FSH is a key reproductive hormone involved in the control of ovarian folliculogenesis and steroidogenesis. Multiple regulatory mechanisms govern the release of…”
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Central actions of ovarian steroids in the feedback regulation of pulsatile secretion of luteinizing hormone by KARSCH, F. J

“…I have considered the neural organization of the system responsible for pulsatile LH and GnRH secretion and have described the feedback actions of two ovarian…”
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Seasonal changes of gonadotropin-releasing hormone secretion in the ewe by Barrell, G.K. (Lincoln University, Canterbury, New Zealand), Moenter, S.M, Caraty, A, Karsch, F.J

“…A sustained volley of high-frequency, pulses of GnRH secretion is a fundamental step in the sequence of neuroendocrine events leading to ovulation during the…”
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Thyroxine is permissive to seasonal transitions in reproductive neuroendocrine activity in the ewe by Dahl, G.E. (University of Michigan, Ann Arbor, MI.), Evans, N.P, Thrun, L.A, Karsch, F.J

“…The observation that circulating thyroxine concentration increases during the breeding season of the ewe, coupled with the finding that thyroid hormones are…”
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Pattern of gonadotropin-releasing hormone (GnRH) secretion leading up to ovulation in the ewe: existence of a preovulatory GnRH surge by Moenter, S M, Caraty, A, Locatelli, A, Karsch, F J

“…We have previously shown LH surges induced by physiological estradiol levels are invariably accompanied by robust and sustained GnRH surges in the ewe. Such an…”
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Steroid feedback inhibition of pulsatile secretion of gonadotropin-releasing hormone in the ewe by KARSCH, F. J, CUMMINS, J. T, THOMAS, G. B, CLARKE, I. J

“…The long-term negative feedback effects of sustained elevations in circulating estradiol and progesterone on the pulsatile secretion of gonadotropin-releasing…”
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Importance of Photoperiodic Signal Quality to Entrainment of the Circannual Reproductive Rhythm of the Ewe by BARRELL, Graham K, THRUN, Lori A, BROWN, Martha E, VIGUIE, Catherine, KARSCH, Fred J

“…An endogenous circannual rhythm drives the seasonal reproductive cycle of a broad spectrum of species. This rhythm is synchronized to the seasons (i.e.,…”
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Distribution of estrogen receptor-immunoreactive cells in the sheep brain by Lehman, M N, Ebling, F J, Moenter, S M, Karsch, F J

“…The distribution of immunoreactive (IR) estrogen receptor (ER)-containing cells was studied in the brains of adult Suffolk ewes using a rat monoclonal antibody…”
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Stress and the control of LH secretion in the ewe by Smith, R F, Ghuman, S P S, Evans, N P, Karsch, F J, Dobson, H

“…Stress influences the activity of the reproductive system at several sites. One of the most significant effects is at level of the GnRH secretory system to…”
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The estradiol-induced surge of gonadotropin-releasing hormone in the ewe by Moenter, S M, Caraty, A, Karsch, F J

“…Previous studies suggest two roles for estradiol in inducing the LH surge in ewes: a neural action to evoke a sudden release of GnRH and a pituitary action to…”
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Mechanisms for endotoxin-induced disruption of ovarian cyclicity: observations in sheep by Karsch, F J, Battaglia, D F

“…This review summarizes a series of experiments that address mechanisms by which endotoxin, a commonly used model of immune/inflammatory challenge, disrupts the…”
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Seasonal plasticity in the brain: the use of large animal models for neuroanatomical research by Lehman, M N, Coolen, L M, Goodman, R L, Viguié, C, Billings, H J, Karsch, F J

“…Seasonally breeding mammals display an annual cycle of fertility that is associated with both structural neuroplasticity and functional changes in the activity…”
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Progesterone blocks the estradiol-induced gonadotropin discharge in the ewe by inhibiting the surge of gonadotropin-releasing hormone by Kasa-Vubu, J Z, Dahl, G E, Evans, N P, Thrun, L A, Moenter, S M, Padmanabhan, V, Karsch, F J

“…Previous studies indicate an elevation of circulating progesterone blocks the positive feedback effect of a rise in circulating estradiol. This explains the…”
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