The Experts below are selected from a list of 228 Experts worldwide ranked by ideXlab platform

Ronald M. Lechan - One of the best experts on this subject based on the ideXlab platform.

  • Induction of Type 2 Iodothyronine Deiodinase in the Mediobasal Hypothalamus by Bacterial Lipopolysaccharide: Role of Corticosterone
    Endocrinology, 2008
    Co-Authors: Edith Sánchez, Praful S. Singru, Csaba Fekete, Ronald M. Lechan
    Abstract:

    To determine whether endotoxin-induced activation of type 2 iodothyronine deiodinase (D2) in the Mediobasal Hypothalamus is dependent on circulating levels of corticosterone, the effect of bacterial lipopolysaccharide (LPS) on D2 gene expression was studied in adrenalectomized, corticosterone-clamped adult, male, Sprague Dawley rats. In sham-adrenalectomized animals, LPS (250 μg/100 g body weight) increased circulating levels of corticosterone and IL-6, as well as tanycyte D2 mRNA in the Mediobasal Hypothalamus. Adrenalectomized, corticosterone-clamped animals showed no significant rise in corticosterone after LPS, compared with saline-treated controls but increased IL-6 levels and tanycyte D2 mRNA similar to LPS-treated sham controls. To further clarify the potential role of corticosterone in the regulation of D2 gene expression by LPS, animals were administered high doses of corticosterone to attain levels similar to that observed in the LPS-treated group. No significant increase in D2 mRNA was observed in the Mediobasal Hypothalamus with the exception of a small subpopulation of cells in the lateral walls of the third ventricle. These data indicate that the LPS-induced increase in D2 mRNA in the Mediobasal Hypothalamus is largely independent of circulating corticosterone and indicate that mechanisms other than adrenal activation are involved in the regulation of most tanycyte D2-expressing cells by endotoxin.

  • Bacterial lipopolysaccharide (LPS)-induced type 2 iodothyronine deiodinase (D2) activation in the Mediobasal Hypothalamus (MBH) is independent of the LPS-induced fall in serum thyroid hormone levels.
    Brain research, 2005
    Co-Authors: Csaba Fekete, Sumit Sarkar, Marcelo A. Christoffolete, Charles H. Emerson, Antonio C. Bianco, Ronald M. Lechan
    Abstract:

    By administration of bacterial lipopolysaccharide (LPS) to intact and T4-replaced thyroidectomized rats, we demonstrate that in contrast to the cortex and anterior pituitary, there is a persistent increase in type 2 iodothyronine deiodinase (D2) activity in the Mediobasal Hypothalamus (MBH). We propose that endotoxin-induced D2 activation in the MBH is independent of circulating levels of thyroid hormone and that this mechanism may contribute to central hypothyroidism associated with infection.

Tsutomu Sawada - One of the best experts on this subject based on the ideXlab platform.

  • Expression of estrogen receptor α and β genes in the Mediobasal Hypothalamus, pituitary and ovary during the canine estrous cycle
    Neuroscience letters, 2003
    Co-Authors: Shingo Hatoya, Ryuzo Torii, Noritoshi Kawate, Hiromichi Tamada, Daijiro Kumagai, Kikuya Sugiura, Tsutomu Sawada, Toshio Inaba
    Abstract:

    Estrogen receptor alpha (ERalpha) and ERbeta mRNA levels were measured in the Mediobasal Hypothalamus, the anterior pituitary and the ovary of beagle bitches at various stages of the estrous cycle. With polymerase chain reaction analysis we detected ERbeta gene transcripts in all tissue samples. The levels of hypothalamic and pituitary ERalpha and beta mRNAs increased from mid anestrus to proestrus and declined thereafter. In the ovary, ERalpha mRNA levels increased from proestrus to diestrus and were positively correlated with plasma progesterone levels (r=0.62, P

  • expression of estrogen receptor α and β genes in the Mediobasal Hypothalamus pituitary and ovary during the canine estrous cycle
    Neuroscience Letters, 2003
    Co-Authors: Shingo Hatoya, Ryuzo Torii, Noritoshi Kawate, Hiromichi Tamada, Daijiro Kumagai, Kikuya Sugiura, Tsutomu Sawada, Toshio Inaba
    Abstract:

    Estrogen receptor α (ERα) and ERβ mRNA levels were measured in the Mediobasal Hypothalamus, the anterior pituitary and the ovary of beagle bitches at various stages of the estrous cycle. With polymerase chain reaction analysis we detected ERβ gene transcripts in all tissue samples. The levels of hypothalamic and pituitary ERα and β mRNAs increased from mid anestrus to proestrus and declined thereafter. In the ovary, ERα mRNA levels increased from proestrus to diestrus and were positively correlated with plasma progesterone levels (r=0.62, P<0.01), whereas ERβ mRNA levels increased from mid anestrus to proestrus and were positively correlated with plasma estradiol-17β levels (r=0.73, P<0.001). These results suggest that the rise in hypothalamic and pituitary ERα and β mRNAs is associated with termination of anestrus, and that increases in ovarian ERα and β mRNAs may be involved in initiating development of the follicle or corpora lutea.

  • expression of estrogen receptor α and β genes in the Mediobasal Hypothalamus pituitary and ovary during the canine estrous cycle
    Neuroscience Letters, 2003
    Co-Authors: Shingo Hatoya, Ryuzo Torii, Noritoshi Kawate, Hiromichi Tamada, Daijiro Kumagai, Kikuya Sugiura, Tsutomu Sawada, Toshio Inaba
    Abstract:

    Estrogen receptor alpha (ERalpha) and ERbeta mRNA levels were measured in the Mediobasal Hypothalamus, the anterior pituitary and the ovary of beagle bitches at various stages of the estrous cycle. With polymerase chain reaction analysis we detected ERbeta gene transcripts in all tissue samples. The levels of hypothalamic and pituitary ERalpha and beta mRNAs increased from mid anestrus to proestrus and declined thereafter. In the ovary, ERalpha mRNA levels increased from proestrus to diestrus and were positively correlated with plasma progesterone levels (r=0.62, P<0.01), whereas ERbeta mRNA levels increased from mid anestrus to proestrus and were positively correlated with plasma estradiol-17beta levels (r=0.73, P<0.001). These results suggest that the rise in hypothalamic and pituitary ERalpha and beta mRNAs is associated with termination of anestrus, and that increases in ovarian ERalpha and beta mRNAs may be involved in initiating development of the follicle or corpora lutea.

  • enhancement of estrogen receptor gene expression in the Mediobasal Hypothalamus during anestrus in the beagle bitch
    Neuroscience Letters, 1997
    Co-Authors: Hiroyuki Tani, Toshio Inaba, Satoshi Matsuyama, Ryuzo Torii, Hiromichi Tamada, Yasuhiko Takamori, Hiroshi Takano, Tsutomu Sawada
    Abstract:

    Abstract Estrogen receptor mRNA (ER mRNA) levels were measured in the Mediobasal Hypothalamus (MBH) of beagle bitches at different stages of the estrous cycle, and compared with levels in ovariectomized (OVX) estrogen-treated bitches. In cyclic bitches, the level of hypothalamic ER mRNA increased during the progression of anestrus and declined thereafter. Hypothalamic ER mRNA and plasma luteinizing hormone (LH) levels during anestrus and proestrus were positively correlated ( r =0.94, P

  • Enhancement of estrogen receptor gene expression in the Mediobasal Hypothalamus during anestrus in the beagle bitch.
    Neuroscience letters, 1997
    Co-Authors: Hiroyuki Tani, Toshio Inaba, Satoshi Matsuyama, Ryuzo Torii, Hiromichi Tamada, Yasuhiko Takamori, Hiroshi Takano, Tsutomu Sawada
    Abstract:

    Estrogen receptor mRNA (ER mRNA) levels were measured in the Mediobasal Hypothalamus (MBH) of beagle bitches at different stages of the estrous cycle, and compared with levels in ovariectomized (OVX) estrogen-treated bitches. In cyclic bitches, the level of hypothalamic ER mRNA increased during the progression of anestrus and declined thereafter. Hypothalamic ER mRNA and plasma luteinizing hormone (LH) levels during anestrus and proestrus were positively correlated (r = 0.94, P < 0.001). In OVX bitches, levels of hypothalamic ER mRNA were low, and increased significantly after treatment with a low dose of estradiol benzoate. These results suggest that, during the course of anestrus in the bitch, hypothalamic ER mRNA expression increases, and may be up-regulated by estradiol.

Csaba Fekete - One of the best experts on this subject based on the ideXlab platform.

  • Induction of Type 2 Iodothyronine Deiodinase in the Mediobasal Hypothalamus by Bacterial Lipopolysaccharide: Role of Corticosterone
    Endocrinology, 2008
    Co-Authors: Edith Sánchez, Praful S. Singru, Csaba Fekete, Ronald M. Lechan
    Abstract:

    To determine whether endotoxin-induced activation of type 2 iodothyronine deiodinase (D2) in the Mediobasal Hypothalamus is dependent on circulating levels of corticosterone, the effect of bacterial lipopolysaccharide (LPS) on D2 gene expression was studied in adrenalectomized, corticosterone-clamped adult, male, Sprague Dawley rats. In sham-adrenalectomized animals, LPS (250 μg/100 g body weight) increased circulating levels of corticosterone and IL-6, as well as tanycyte D2 mRNA in the Mediobasal Hypothalamus. Adrenalectomized, corticosterone-clamped animals showed no significant rise in corticosterone after LPS, compared with saline-treated controls but increased IL-6 levels and tanycyte D2 mRNA similar to LPS-treated sham controls. To further clarify the potential role of corticosterone in the regulation of D2 gene expression by LPS, animals were administered high doses of corticosterone to attain levels similar to that observed in the LPS-treated group. No significant increase in D2 mRNA was observed in the Mediobasal Hypothalamus with the exception of a small subpopulation of cells in the lateral walls of the third ventricle. These data indicate that the LPS-induced increase in D2 mRNA in the Mediobasal Hypothalamus is largely independent of circulating corticosterone and indicate that mechanisms other than adrenal activation are involved in the regulation of most tanycyte D2-expressing cells by endotoxin.

  • Bacterial lipopolysaccharide (LPS)-induced type 2 iodothyronine deiodinase (D2) activation in the Mediobasal Hypothalamus (MBH) is independent of the LPS-induced fall in serum thyroid hormone levels.
    Brain research, 2005
    Co-Authors: Csaba Fekete, Sumit Sarkar, Marcelo A. Christoffolete, Charles H. Emerson, Antonio C. Bianco, Ronald M. Lechan
    Abstract:

    By administration of bacterial lipopolysaccharide (LPS) to intact and T4-replaced thyroidectomized rats, we demonstrate that in contrast to the cortex and anterior pituitary, there is a persistent increase in type 2 iodothyronine deiodinase (D2) activity in the Mediobasal Hypothalamus (MBH). We propose that endotoxin-induced D2 activation in the MBH is independent of circulating levels of thyroid hormone and that this mechanism may contribute to central hypothyroidism associated with infection.

  • lipopolysaccharide induces type 2 iodothyronine deiodinase in the Mediobasal Hypothalamus implications for the nonthyroidal illness syndrome
    Endocrinology, 2004
    Co-Authors: Csaba Fekete, Sumit Sarkar, Antonio C. Bianco, Balazs Gereben, Marton Doleschall, John W Harney, Jose Miguel Dora, Zsolt Liposits, William M Rand, Charles P Emerson
    Abstract:

    To determine whether the type 2 iodothyronine deiodinase (D2), the principal central nervous system enzyme converting T4 to biologically active T3, is regulated in tanycytes by immune activation, D2 activity was measured in the Mediobasal Hypothalamus (MBH) 4, 12, and 24 h after administration of bacterial lipopolysaccharide (LPS) and compared with D2 levels in the cortex and anterior pituitary of rats. In contrast to D2 activity in the cortex and anterior pituitary that showed a steady linear increase over 24 h, which was coincident with a decline in thyroid hormone and TSH levels, D2 activity peaked in the MBH 12 h after LPS administration. By in situ hybridization, the increased D2 mRNA synthesis induced by LPS was specifically localized to tanycytes lining the third ventricle. In vitro assays in HC11 and HEK-293 cells demonstrated that the p65 subunit of nuclear factor-κB markedly increased both rat and human D2 genes (dio2) as analyzed by promoter assays. No activation of human dio2 was observed when...

Toshio Inaba - One of the best experts on this subject based on the ideXlab platform.

  • Expression of estrogen receptor α and β genes in the Mediobasal Hypothalamus, pituitary and ovary during the canine estrous cycle
    Neuroscience letters, 2003
    Co-Authors: Shingo Hatoya, Ryuzo Torii, Noritoshi Kawate, Hiromichi Tamada, Daijiro Kumagai, Kikuya Sugiura, Tsutomu Sawada, Toshio Inaba
    Abstract:

    Estrogen receptor alpha (ERalpha) and ERbeta mRNA levels were measured in the Mediobasal Hypothalamus, the anterior pituitary and the ovary of beagle bitches at various stages of the estrous cycle. With polymerase chain reaction analysis we detected ERbeta gene transcripts in all tissue samples. The levels of hypothalamic and pituitary ERalpha and beta mRNAs increased from mid anestrus to proestrus and declined thereafter. In the ovary, ERalpha mRNA levels increased from proestrus to diestrus and were positively correlated with plasma progesterone levels (r=0.62, P

  • expression of estrogen receptor α and β genes in the Mediobasal Hypothalamus pituitary and ovary during the canine estrous cycle
    Neuroscience Letters, 2003
    Co-Authors: Shingo Hatoya, Ryuzo Torii, Noritoshi Kawate, Hiromichi Tamada, Daijiro Kumagai, Kikuya Sugiura, Tsutomu Sawada, Toshio Inaba
    Abstract:

    Estrogen receptor α (ERα) and ERβ mRNA levels were measured in the Mediobasal Hypothalamus, the anterior pituitary and the ovary of beagle bitches at various stages of the estrous cycle. With polymerase chain reaction analysis we detected ERβ gene transcripts in all tissue samples. The levels of hypothalamic and pituitary ERα and β mRNAs increased from mid anestrus to proestrus and declined thereafter. In the ovary, ERα mRNA levels increased from proestrus to diestrus and were positively correlated with plasma progesterone levels (r=0.62, P<0.01), whereas ERβ mRNA levels increased from mid anestrus to proestrus and were positively correlated with plasma estradiol-17β levels (r=0.73, P<0.001). These results suggest that the rise in hypothalamic and pituitary ERα and β mRNAs is associated with termination of anestrus, and that increases in ovarian ERα and β mRNAs may be involved in initiating development of the follicle or corpora lutea.

  • expression of estrogen receptor α and β genes in the Mediobasal Hypothalamus pituitary and ovary during the canine estrous cycle
    Neuroscience Letters, 2003
    Co-Authors: Shingo Hatoya, Ryuzo Torii, Noritoshi Kawate, Hiromichi Tamada, Daijiro Kumagai, Kikuya Sugiura, Tsutomu Sawada, Toshio Inaba
    Abstract:

    Estrogen receptor alpha (ERalpha) and ERbeta mRNA levels were measured in the Mediobasal Hypothalamus, the anterior pituitary and the ovary of beagle bitches at various stages of the estrous cycle. With polymerase chain reaction analysis we detected ERbeta gene transcripts in all tissue samples. The levels of hypothalamic and pituitary ERalpha and beta mRNAs increased from mid anestrus to proestrus and declined thereafter. In the ovary, ERalpha mRNA levels increased from proestrus to diestrus and were positively correlated with plasma progesterone levels (r=0.62, P<0.01), whereas ERbeta mRNA levels increased from mid anestrus to proestrus and were positively correlated with plasma estradiol-17beta levels (r=0.73, P<0.001). These results suggest that the rise in hypothalamic and pituitary ERalpha and beta mRNAs is associated with termination of anestrus, and that increases in ovarian ERalpha and beta mRNAs may be involved in initiating development of the follicle or corpora lutea.

  • enhancement of aromatase gene expression in the Mediobasal Hypothalamus during anestrus in the beagle bitch
    Neuroscience Letters, 2002
    Co-Authors: Toshio Inaba, Hiroyuki Tani, Tamaki Namura, Satoshi Matsuyama, Ryuzo Torii, Noritoshi Kawate, Hiromichi Tamada, Shingo Hatoya, Daijiro Kumagai, Kikuya Sugiura
    Abstract:

    The relationships among expression of cytochrome P450 aromatase (P450arom) mRNA in the Mediobasal Hypothalamus (MBH), ovarian aromatase activity, and estrogen secretion were examined throughout the estrous cycle in beagle bitches. Using polymerase chain reaction (PCR) analysis we were able to detect P450arom gene transcripts in the canine MBH. The level of hypothalamic P450arom mRNA increased during the progression of anestrus and declined thereafter. Ovarian P450arom activity, as measured by a 3H2O assay, were low in anestrus, increased in proestrus, and declined thereafter. Ovarian P450arom activity and plasma estradiol-17β levels were positively correlated (r=0.77, P<0.05). These results suggest that enhancement of hypothalamic P450arom gene expression is associated with termination of anestrus.

  • Enhancement of aromatase gene expression in the Mediobasal Hypothalamus during anestrus in the beagle bitch.
    Neuroscience Letters, 2002
    Co-Authors: Toshio Inaba, Hiroyuki Tani, Tamaki Namura, Satoshi Matsuyama, Ryuzo Torii, Noritoshi Kawate, Hiromichi Tamada, Shingo Hatoya, Daijiro Kumagai, Kikuya Sugiura
    Abstract:

    The relationships among expression of cytochrome P450 aromatase (P450arom) mRNA in the Mediobasal Hypothalamus (MBH), ovarian aromatase activity, and estrogen secretion were examined throughout the estrous cycle in beagle bitches. Using polymerase chain reaction (PCR) analysis we were able to detect P450arom gene transcripts in the canine MBH. The level of hypothalamic P450arom mRNA increased during the progression of anestrus and declined thereafter. Ovarian P450arom activity, as measured by a 3H2O assay, were low in anestrus, increased in proestrus, and declined thereafter. Ovarian P450arom activity and plasma estradiol-17β levels were positively correlated (r=0.77, P

Ryuzo Torii - One of the best experts on this subject based on the ideXlab platform.

  • Expression of estrogen receptor α and β genes in the Mediobasal Hypothalamus, pituitary and ovary during the canine estrous cycle
    Neuroscience letters, 2003
    Co-Authors: Shingo Hatoya, Ryuzo Torii, Noritoshi Kawate, Hiromichi Tamada, Daijiro Kumagai, Kikuya Sugiura, Tsutomu Sawada, Toshio Inaba
    Abstract:

    Estrogen receptor alpha (ERalpha) and ERbeta mRNA levels were measured in the Mediobasal Hypothalamus, the anterior pituitary and the ovary of beagle bitches at various stages of the estrous cycle. With polymerase chain reaction analysis we detected ERbeta gene transcripts in all tissue samples. The levels of hypothalamic and pituitary ERalpha and beta mRNAs increased from mid anestrus to proestrus and declined thereafter. In the ovary, ERalpha mRNA levels increased from proestrus to diestrus and were positively correlated with plasma progesterone levels (r=0.62, P

  • expression of estrogen receptor α and β genes in the Mediobasal Hypothalamus pituitary and ovary during the canine estrous cycle
    Neuroscience Letters, 2003
    Co-Authors: Shingo Hatoya, Ryuzo Torii, Noritoshi Kawate, Hiromichi Tamada, Daijiro Kumagai, Kikuya Sugiura, Tsutomu Sawada, Toshio Inaba
    Abstract:

    Estrogen receptor α (ERα) and ERβ mRNA levels were measured in the Mediobasal Hypothalamus, the anterior pituitary and the ovary of beagle bitches at various stages of the estrous cycle. With polymerase chain reaction analysis we detected ERβ gene transcripts in all tissue samples. The levels of hypothalamic and pituitary ERα and β mRNAs increased from mid anestrus to proestrus and declined thereafter. In the ovary, ERα mRNA levels increased from proestrus to diestrus and were positively correlated with plasma progesterone levels (r=0.62, P<0.01), whereas ERβ mRNA levels increased from mid anestrus to proestrus and were positively correlated with plasma estradiol-17β levels (r=0.73, P<0.001). These results suggest that the rise in hypothalamic and pituitary ERα and β mRNAs is associated with termination of anestrus, and that increases in ovarian ERα and β mRNAs may be involved in initiating development of the follicle or corpora lutea.

  • expression of estrogen receptor α and β genes in the Mediobasal Hypothalamus pituitary and ovary during the canine estrous cycle
    Neuroscience Letters, 2003
    Co-Authors: Shingo Hatoya, Ryuzo Torii, Noritoshi Kawate, Hiromichi Tamada, Daijiro Kumagai, Kikuya Sugiura, Tsutomu Sawada, Toshio Inaba
    Abstract:

    Estrogen receptor alpha (ERalpha) and ERbeta mRNA levels were measured in the Mediobasal Hypothalamus, the anterior pituitary and the ovary of beagle bitches at various stages of the estrous cycle. With polymerase chain reaction analysis we detected ERbeta gene transcripts in all tissue samples. The levels of hypothalamic and pituitary ERalpha and beta mRNAs increased from mid anestrus to proestrus and declined thereafter. In the ovary, ERalpha mRNA levels increased from proestrus to diestrus and were positively correlated with plasma progesterone levels (r=0.62, P<0.01), whereas ERbeta mRNA levels increased from mid anestrus to proestrus and were positively correlated with plasma estradiol-17beta levels (r=0.73, P<0.001). These results suggest that the rise in hypothalamic and pituitary ERalpha and beta mRNAs is associated with termination of anestrus, and that increases in ovarian ERalpha and beta mRNAs may be involved in initiating development of the follicle or corpora lutea.

  • enhancement of aromatase gene expression in the Mediobasal Hypothalamus during anestrus in the beagle bitch
    Neuroscience Letters, 2002
    Co-Authors: Toshio Inaba, Hiroyuki Tani, Tamaki Namura, Satoshi Matsuyama, Ryuzo Torii, Noritoshi Kawate, Hiromichi Tamada, Shingo Hatoya, Daijiro Kumagai, Kikuya Sugiura
    Abstract:

    The relationships among expression of cytochrome P450 aromatase (P450arom) mRNA in the Mediobasal Hypothalamus (MBH), ovarian aromatase activity, and estrogen secretion were examined throughout the estrous cycle in beagle bitches. Using polymerase chain reaction (PCR) analysis we were able to detect P450arom gene transcripts in the canine MBH. The level of hypothalamic P450arom mRNA increased during the progression of anestrus and declined thereafter. Ovarian P450arom activity, as measured by a 3H2O assay, were low in anestrus, increased in proestrus, and declined thereafter. Ovarian P450arom activity and plasma estradiol-17β levels were positively correlated (r=0.77, P<0.05). These results suggest that enhancement of hypothalamic P450arom gene expression is associated with termination of anestrus.

  • Enhancement of aromatase gene expression in the Mediobasal Hypothalamus during anestrus in the beagle bitch.
    Neuroscience Letters, 2002
    Co-Authors: Toshio Inaba, Hiroyuki Tani, Tamaki Namura, Satoshi Matsuyama, Ryuzo Torii, Noritoshi Kawate, Hiromichi Tamada, Shingo Hatoya, Daijiro Kumagai, Kikuya Sugiura
    Abstract:

    The relationships among expression of cytochrome P450 aromatase (P450arom) mRNA in the Mediobasal Hypothalamus (MBH), ovarian aromatase activity, and estrogen secretion were examined throughout the estrous cycle in beagle bitches. Using polymerase chain reaction (PCR) analysis we were able to detect P450arom gene transcripts in the canine MBH. The level of hypothalamic P450arom mRNA increased during the progression of anestrus and declined thereafter. Ovarian P450arom activity, as measured by a 3H2O assay, were low in anestrus, increased in proestrus, and declined thereafter. Ovarian P450arom activity and plasma estradiol-17β levels were positively correlated (r=0.77, P