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Magata F, Tsukamura H, Matsuda F. The impact of inflammatory stress on hypothalamic kisspeptin neurons: Mechanisms underlying inflammation-associated infertility in humans and domestic animals. Peptides 2023; 162:170958. [PMID: 36682622 DOI: 10.1016/j.peptides.2023.170958] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/27/2022] [Accepted: 01/17/2023] [Indexed: 01/21/2023]
Abstract
Inflammatory diseases attenuate reproductive functions in humans and domestic animals. Lipopolysaccharide (LPS), an endotoxin released by bacteria, is known to disrupt female reproductive functions in various inflammatory diseases. LPS administration has been used to elucidate the impact of pathophysiological activation of the immune system on reproduction. Hypothalamic kisspeptin neurons are the master regulators of mammalian reproduction, mediating direct stimulation of hypothalamic gonadotropin-releasing hormone (GnRH) release and consequent release of gonadotropins, such as luteinizing hormone (LH) and follicle-stimulating hormone from the pituitary. The discovery of kisspeptin neurons in the mammalian hypothalamus has drastically advanced our understanding of how inflammatory stress causes reproductive dysfunction in both humans and domestic animals. Inflammation-induced ovarian dysfunction could be caused, at least partly, by aberrant GnRH and LH secretion, which is regulated by kisspeptin signaling. In this review, we focus on the effects of LPS on hypothalamic kisspeptin neurons to outline the impact of inflammatory stress on neuroendocrine regulation of mammalian reproductive systems. First, we summarize the attenuation of female reproduction by LPS during inflammation and the effects of LPS on ovarian and pituitary function. Second, we outline the inhibitory effects of LPS on pulsatile- and surge-mode GnRH/LH release. Third, we discuss the LPS-responsive hypothalamic-pituitary-adrenal axis and hypothalamic neural systems in terms of the cytokine-mediated pathway and the possible direct action of LPS via its hypothalamic receptors. This article describes the impact of LPS on hypothalamic kisspeptin neurons and the possible mechanisms underlying LPS-mediated disruption of LH pulses/surge via kisspeptin neurons.
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Affiliation(s)
- Fumie Magata
- Department of Veterinary Medical Sciences, the University of Tokyo, Tokyo 113-8657, Japan.
| | - Hiroko Tsukamura
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan.
| | - Fuko Matsuda
- Department of Veterinary Medical Sciences, the University of Tokyo, Tokyo 113-8657, Japan.
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Magata F, Toda L, Sato M, Sakono T, Chambers JK, Uchida K, Tsukamura H, Matsuda F. Intrauterine LPS inhibited arcuate Kiss1 expression, LH pulses, and ovarian function in rats. Reproduction 2022; 164:207-219. [PMID: 36099331 DOI: 10.1530/rep-22-0047] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 09/12/2022] [Indexed: 11/08/2022]
Abstract
In brief Uterine inflammatory diseases are a major cause of infertility in humans and domestic animals. The current findings that intrauterine lipopolysaccharide is absorbed in systemic circulation and attenuates ovarian cyclic activities could provide a basis for developing novel treatments to improve fertility. Abstract Uterine inflammatory diseases are a major cause of infertility in humans and domestic animals. Circulating lipopolysaccharide (LPS), a bacterial endotoxin causing uterine inflammation, reportedly downregulates the hypothalamic-pituitary-gonadal axis to mediate ovarian dysfunction. In contrast, the mechanism whereby intrauterine LPS affects ovarian function has not been fully clarified. This study aimed to elucidate whether uterine exposure to LPS downregulates hypothalamic kisspeptin gene (Kiss1) expression, gonadotropin release, and ovarian function. Uterine inflammation was induced by intrauterine LPS administration to ovary-intact and ovariectomized female rats. As a result, plasma LPS concentrations were substantially higher in control rats until 48 h post injection, and the estrous cyclicity was disrupted with a prolonged diestrous phase. Three days post injection, the number of Graafian follicles and plasma estradiol concentration were reduced in LPS-treated rats, while numbers of Kiss1-expressing cells in the anteroventral periventricular nucleus and arcuate nucleus (ARC) were comparable in ovary-intact rats. Four days post injection, ovulation rate and plasma progesterone levels reduced significantly while gene expression of interleukin1β and tumor necrosis factor α was upregulated in the ovaries of LPS-treated rats that failed to ovulate. Furthermore, the number of Kiss1-expressing cells in the ARC and pulsatile luteinizing hormone (LH) release were significantly reduced in ovariectomized rats 24 h post injection. In conclusion, these results indicate that intrauterine LPS is absorbed in systemic circulation and attenuates ovarian function. This detrimental effect might be caused, at least partly, by the inhibition of ARC Kiss1 expression and LH pulses along with an induction of ovarian inflammatory response.
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Affiliation(s)
- Fumie Magata
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
| | - Lisa Toda
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
| | - Marimo Sato
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
| | - Takahiro Sakono
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
| | - James K Chambers
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
| | - Kazuyuki Uchida
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
| | - Hiroko Tsukamura
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Fuko Matsuda
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
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McCosh RB, Breen KM, Kauffman AS. Neural and endocrine mechanisms underlying stress-induced suppression of pulsatile LH secretion. Mol Cell Endocrinol 2019; 498:110579. [PMID: 31521706 PMCID: PMC6874223 DOI: 10.1016/j.mce.2019.110579] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/30/2019] [Accepted: 09/10/2019] [Indexed: 12/21/2022]
Abstract
Stress is well-known to inhibit a variety of reproductive processes, including the suppression of episodic Gonadotropin releasing hormone (GnRH) secretion, typically measured via downstream luteinizing hormone (LH) secretion. Since pulsatile secretion of GnRH and LH are necessary for proper reproductive function in both males and females, and stress is common for both human and animals, understanding the fundamental mechanisms by which stress impairs LH pulses is of critical importance. Activation of the hypothalamic-pituitary-adrenal axis, and its corresponding endocrine factors, is a key feature of the stress response, so dissecting the role of stress hormones, including corticotrophin releasing hormone (CRH) and corticosterone, in the inhibition of LH secretion has been one key research focus. However, some evidence suggests that these stress hormones alone are not sufficient for the full inhibition of LH caused by stress, implicating the additional involvement of other hormonal or neural signaling pathways in this process (including inputs from the brainstem, amygdala, parabrachial nucleus, and dorsomedial nucleus). Moreover, different stress types, such as metabolic stress (hypoglycemia), immune stress, and psychosocial stress, appear to suppress LH secretion via partially unique neural and endocrine pathways. The mechanisms underlying the suppression of LH pulses in these models offer interesting comparisons and contrasts, including the specific roles of amygdaloid nuclei and CRH receptor types. This review focuses on the most recent and emerging insights into endocrine and neural mechanisms responsible for the suppression of pulsatile LH secretion in mammals, and offers insights in important gaps in knowledge.
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Affiliation(s)
- Richard B McCosh
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0674, USA
| | - Kellie M Breen
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0674, USA
| | - Alexander S Kauffman
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0674, USA.
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Lainez NM, Coss D. Obesity, Neuroinflammation, and Reproductive Function. Endocrinology 2019; 160:2719-2736. [PMID: 31513269 PMCID: PMC6806266 DOI: 10.1210/en.2019-00487] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 09/04/2019] [Indexed: 12/13/2022]
Abstract
The increasing occurrence of obesity has become a significant public health concern. Individuals with obesity have higher prevalence of heart disease, stroke, osteoarthritis, diabetes, and reproductive disorders. Reproductive problems include menstrual irregularities, pregnancy complications, and infertility due to anovulation, in women, and lower testosterone and diminished sperm count, in men. In particular, women with obesity have reduced levels of both gonadotropin hormones, and, in obese men, lower testosterone is accompanied by diminished LH. Taken together, these findings indicate central dysregulation of the hypothalamic-pituitary-gonadal axis, specifically at the level of the GnRH neuron function, which is the final brain output for the regulation of reproduction. Obesity is a state of hyperinsulinemia, hyperlipidemia, hyperleptinemia, and chronic inflammation. Herein, we review recent advances in our understanding of how these metabolic and immune changes affect hypothalamic function and regulation of GnRH neurons. In the latter part, we focus on neuroinflammation as a major consequence of obesity and discuss findings that reveal that GnRH neurons are uniquely positioned to respond to inflammatory changes.
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Affiliation(s)
- Nancy M Lainez
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California
| | - Djurdjica Coss
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California
- Correspondence: Djurdjica Coss, PhD, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, 303 SOM Research Building, 900 University Avenue, Riverside, California 92521. E-mail:
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Lainez NM, Coss D. Leukemia Inhibitory Factor Represses GnRH Gene Expression via cFOS during Inflammation in Male Mice. Neuroendocrinology 2019; 108:291-307. [PMID: 30630179 PMCID: PMC6561803 DOI: 10.1159/000496754] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 01/09/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND The mechanisms whereby neuroinflammation negatively affects neuronal function in the hypothalamus are not clear. Our previous study determined that obesity-mediated chronic inflammation elicits sex-specific impairment in reproductive function via reduction in spine density in gonadotropin-releasing hormone (GnRH) neurons. Neuroinflammation and subsequent decrease in GnRH neuron spine density was specific for male mice, while protection in females was independent of ovarian estrogens. METHODS To examine if neuroinflammation-induced cytokines can directly regulate GnRH gene expression, herein we examined signaling pathways and mechanisms in males in vivo and in GnRH-expressing cell line, GT1-7. RESULTS GnRH neurons express cytokine receptors, and chronic or acute neuroinflammation represses GnRH gene expression in vivo. Leukemia inhibitory factor (LIF) in particular represses GnRH expression in GT1-7 cells, while other cytokines do not. STAT3 and MAPK pathways are activated following LIF treatment, but only MAPK pathway, specifically p38α, is sufficient to repress the GnRH gene. LIF induces cFOS that represses the GnRH gene via the -1,793 site in the enhancer region. In vivo, following high-fat diet, cFOS is induced in GnRH neurons and neurons juxtaposed to the leaky blood brain barrier of the organum vasculosum of the lamina terminalis, but not in the neurons further away. CONCLUSION Our results indicate that the increase in LIF due to neuroinflammation induces cFOS and represses the GnRH gene. Therefore, in addition to synaptic changes in GnRH neurons, neuroinflammatory cytokines directly regulate gene expression and reproductive function, and the specificity for neuronal targets may stem from the proximity to the fenestrated capillaries.
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Affiliation(s)
- Nancy M Lainez
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, USA
| | - Djurdjica Coss
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, USA,
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Surkin PN, Brenhouse H, Deak T, Liberman AC, Lasaga M. Stress, alcohol and infection during early development: A brief review of common outcomes and mechanisms. J Neuroendocrinol 2018; 30:e12602. [PMID: 29682808 PMCID: PMC6181762 DOI: 10.1111/jne.12602] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 04/17/2018] [Accepted: 04/17/2018] [Indexed: 01/17/2023]
Abstract
Although stress is an adaptive physiological response to deal with adverse conditions, its occurrence during the early stages of life, such as infancy or adolescence, can induce adaptations in multiple physiological systems, including the reproductive axis, the hypothalamic-pituitary-adrenal (HPA) axis, the limbic cortex and the immune system. These early changes have consequences in adult life, as seen in the physiological and behavioural responses to stress. This review highlights the impact of several stress challenges incurred at various stages of development (perinatal, juvenile, adolescent periods) and how the developmental timing of early-life stress confers unique physiological adaptations that may persist across the lifespan. In doing so, we emphasise how intrinsic sex differences in the stress response might contribute to sex-specific vulnerabilities, the molecular processes underlying stress in the adult, and potential therapeutic interventions to mitigate the effects of early stage stress, including the novel molecular mechanism of SUMOylation as a possible key target of HPA regulation during early-life stress.
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Affiliation(s)
- Pablo Nicolás Surkin
- Universidad de Buenos Aires, Facultad de Odontología, Cátedra de Fisiología, Marcelo T. de Alvear 2142, 1122 Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Heather Brenhouse
- Psychology Department, Northeastern University, Boston, MA, United States
| | - Terrence Deak
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University-SUNY, Binghamton, NY 13902-6000, United States
| | - Ana Clara Liberman
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina
| | - Mercedes Lasaga
- INBIOMED Instituto de Investigaciones Biomédicas UBA-CONICET, Facultad de Medicina, UBA, Ciudad Autónoma de Buenos Aires, 1121 ABG, Argentina
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Iwasa T, Matsuzaki T, Yano K, Mayila Y, Irahara M. The roles of kisspeptin and gonadotropin inhibitory hormone in stress-induced reproductive disorders. Endocr J 2018; 65:133-140. [PMID: 29375085 DOI: 10.1507/endocrj.ej18-0026] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Several kinds of stress suppress the hypothalamic-pituitary-gonadal (HPG) axis and reproductive behavior in humans and animals. These changes can eventually cause diseases and disorders, such as amenorrhea and infertility. In previous studies, it has been shown that stress-related factors, e.g., corticotropin-releasing hormone, cortisol, and pro-inflammatory cytokines, promote the stress-induced suppression of the HPG axis. However, these mechanisms are not sufficient to explain how stress suppresses HPG axis activity, and it has been suggested that some other factors might also be involved. In the early 21st century, novel neuroendocrine peptides, kisspeptin and gonadotropin inhibitory hormone (GnIH)/RFamide-related peptide 3 (RFRP-3), which directly regulate GnRH/gonadotropin synthesis and secretion, were newly discovered. Growing evidence indicates that kisspeptin and GnIH/RFRP-3 play pivotal roles in the stress-induced disruption of the HPG axis and reproductive behavior in addition to their physiological functions. This review summarizes what is currently known about the roles of kisspeptin and GnIH/RFRP-3 in stress-induced reproductive disorders.
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Affiliation(s)
- Takeshi Iwasa
- Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503, Japan
| | - Toshiya Matsuzaki
- Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503, Japan
| | - Kiyohito Yano
- Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503, Japan
| | - Yiliyasi Mayila
- Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503, Japan
| | - Minoru Irahara
- Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503, Japan
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8
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Matsuwaki T, Komatsuda M, Fujisawa A, Doke M, Yamanouchi K, Nishihara M. Molecular species of prostaglandins involved in modulating luteinising hormone pulses of female rats under infectious stress conditions. J Neuroendocrinol 2017; 29. [PMID: 28544399 DOI: 10.1111/jne.12490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 04/28/2017] [Accepted: 05/16/2017] [Indexed: 11/28/2022]
Abstract
Mammalian reproductive function is controlled by the hypothalamic-pituitary-gonadal (HPG) axis, which is suppressed under infectious stress conditions. By analysing the pulsatility of luteinising hormone (LH), we have previously demonstrated that prostaglandins (PGs) in the central nervous system mediate infectious stress to suppress the activity of the HPG axis. The present study aimed to characterise the types of PGs responsible for suppression of the HPG axis. We focused on three major types of PGs: PGE2 , PGD2 and PGF2α . We used female rats overiectomised bilaterally 1 week before the experiments. Lipopolysaccharide (100 μg kg-1 ) suppressed LH pulses at the same time as enhancing the concentration of all three PGs in the cerebrospinal fluid, which was restored by indomethacin (10 mg kg-1 ). Subsequently, we observed LH pulsatility after a single injection of each PG and after co-injection of PGE2 with PGF2α into the third cerebral ventricle. A single injection of PGE2 dose-dependently induced a transient increase in mean LH concentration and LH pulse amplitude, and PGD2 significantly increased the amplitude of LH pulses, wereas PGF2α did not affect LH pulsatility. On the other hand, co-injection of PGE2 and PGF2α induced a significant suppression of both the frequency and amplitude of LH pulses. These results suggest that PGE2 and PGF2α can represent two of the mediators that suppress the HPG axis in situations of infectious stress. Moreover, the results imply that there are two contradictory effects of PGE2 on LH pulsatility: (i) enhancive when working alone and (ii) suppressive when working together with PGF2α .
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Affiliation(s)
- T Matsuwaki
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - M Komatsuda
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - A Fujisawa
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - M Doke
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - K Yamanouchi
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - M Nishihara
- Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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9
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Interleukin-18 and its receptor are expressed in gonadotropin-releasing hormone neurons of mouse and rat forebrain. Neurosci Lett 2017; 650:33-37. [DOI: 10.1016/j.neulet.2017.03.051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/20/2017] [Accepted: 03/31/2017] [Indexed: 11/19/2022]
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10
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Camille Melón L, Maguire J. GABAergic regulation of the HPA and HPG axes and the impact of stress on reproductive function. J Steroid Biochem Mol Biol 2016; 160:196-203. [PMID: 26690789 PMCID: PMC4861672 DOI: 10.1016/j.jsbmb.2015.11.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 11/16/2015] [Accepted: 11/26/2015] [Indexed: 11/25/2022]
Abstract
The hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes are regulated by GABAergic signaling at the level of corticotropin-releasing hormone (CRH) and gonadotropin-releasing hormone (GnRH) neurons, respectively. Under basal conditions, activity of CRH and GnRH neurons are controlled in part by both phasic and tonic GABAergic inhibition, mediated by synaptic and extrasynaptic GABAA receptors (GABAARs), respectively. For CRH neurons, this tonic GABAergic inhibition is mediated by extrasynaptic, δ subunit-containing GABAARs. Similarly, a THIP-sensitive tonic GABAergic current has been shown to regulate GnRH neurons, suggesting a role for δ subunit-containing GABAARs; however, this remains to be explicitly demonstrated. GABAARs incorporating the δ subunit confer neurosteroid sensitivity, suggesting a potential role for neurosteroid modulation in the regulation of the HPA and HPG axes. Thus, stress-derived neurosteroids may contribute to the impact of stress on reproductive function. Interestingly, excitatory actions of GABA have been demonstrated in both CRH neurons at the apex of control of the HPA axis and in GnRH neurons which mediate the HPG axis, adding to the complexity for the role of GABAergic signaling in the regulation of these systems. Here we review the effects that stress has on GnRH neurons and HPG axis function alongside evidence supporting GABAARs as a major interface between the stress and reproductive axes.
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Affiliation(s)
- Laverne Camille Melón
- Tufts University School of Medicine, Department of Neuroscience, Boston, MA 02111, United States
| | - Jamie Maguire
- Tufts University School of Medicine, Department of Neuroscience, Boston, MA 02111, United States.
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Prenatal undernutrition results in greater lipopolysaccharide‐induced changes in hypothalamic TNF‐α expression, but does not affect the equivalent changes in the serum levels of luteinizing hormone and testosterone, in adult male rats. Int J Dev Neurosci 2015; 48:80-3. [DOI: 10.1016/j.ijdevneu.2015.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 10/29/2015] [Accepted: 12/03/2015] [Indexed: 11/22/2022] Open
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12
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Munkhzaya M, Matsuzaki T, Iwasa T, Tungalagsuvd A, Kawami T, Kato T, Kuwahara A, Irahara M. The suppressive effect of immune stress on LH secretion is absent in the early neonatal period in rats. Int J Dev Neurosci 2015; 46:38-43. [DOI: 10.1016/j.ijdevneu.2015.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 06/12/2015] [Accepted: 06/30/2015] [Indexed: 10/23/2022] Open
Affiliation(s)
- Munkhsaikhan Munkhzaya
- Department of Obstetrics and GynecologyThe University of Tokushima Graduate SchoolInstitute of Health Biosciences3‐18‐15 Kuramoto‐ChoTokushima770‐8503Japan
| | - Toshiya Matsuzaki
- Department of Obstetrics and GynecologyThe University of Tokushima Graduate SchoolInstitute of Health Biosciences3‐18‐15 Kuramoto‐ChoTokushima770‐8503Japan
| | - Takeshi Iwasa
- Department of Obstetrics and GynecologyThe University of Tokushima Graduate SchoolInstitute of Health Biosciences3‐18‐15 Kuramoto‐ChoTokushima770‐8503Japan
| | - Altankhuu Tungalagsuvd
- Department of Obstetrics and GynecologyThe University of Tokushima Graduate SchoolInstitute of Health Biosciences3‐18‐15 Kuramoto‐ChoTokushima770‐8503Japan
| | - Takako Kawami
- Department of Obstetrics and GynecologyThe University of Tokushima Graduate SchoolInstitute of Health Biosciences3‐18‐15 Kuramoto‐ChoTokushima770‐8503Japan
| | - Takeshi Kato
- Department of Obstetrics and GynecologyThe University of Tokushima Graduate SchoolInstitute of Health Biosciences3‐18‐15 Kuramoto‐ChoTokushima770‐8503Japan
| | - Akira Kuwahara
- Department of Obstetrics and GynecologyThe University of Tokushima Graduate SchoolInstitute of Health Biosciences3‐18‐15 Kuramoto‐ChoTokushima770‐8503Japan
| | - Minoru Irahara
- Department of Obstetrics and GynecologyThe University of Tokushima Graduate SchoolInstitute of Health Biosciences3‐18‐15 Kuramoto‐ChoTokushima770‐8503Japan
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13
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Grachev P, Li XF, Hu MH, Li SY, Millar RP, Lightman SL, O'Byrne KT. Neurokinin B signaling in the female rat: a novel link between stress and reproduction. Endocrinology 2014; 155:2589-601. [PMID: 24708241 DOI: 10.1210/en.2013-2038] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Acute systemic stress disrupts reproductive function by inhibiting pulsatile gonadotropin secretion. The underlying mechanism involves stress-induced suppression of the GnRH pulse generator, the functional unit of which is considered to be the hypothalamic arcuate nucleus kisspeptin/neurokinin B/dynorphin A neurons. Agonists of the neurokinin B (NKB) receptor (NK3R) have been shown to suppress the GnRH pulse generator, in a dynorphin A (Dyn)-dependent fashion, under hypoestrogenic conditions, and Dyn has been well documented to mediate several stress-related central regulatory functions. We hypothesized that the NKB/Dyn signaling cascade is required for stress-induced suppression of the GnRH pulse generator. To investigate this ovariectomized rats, iv administered with Escherichia coli lipopolysaccharide (LPS) following intracerebroventricular pretreatment with NK3R or κ-opioid receptor (Dyn receptor) antagonists, were subjected to frequent blood sampling for hormone analysis. Antagonism of NK3R, but not κ-opioid receptor, blocked the suppressive effect of LPS challenge on LH pulse frequency. Neither antagonist affected LPS-induced corticosterone secretion. Hypothalamic arcuate nucleus NKB neurons project to the paraventricular nucleus, the major hypothalamic source of the stress-related neuropeptides CRH and arginine vasopressin (AVP), which have been implicated in the stress-induced suppression of the hypothalamic-pituitary-gonadal axis. A separate group of ovariectomized rats was, therefore, used to address the potential involvement of central CRH and/or AVP signaling in the suppression of LH pulsatility induced by intracerebroventricular administration of a selective NK3R agonist, senktide. Neither AVP nor CRH receptor antagonists affected the senktide-induced suppression of the LH pulse; however, antagonism of type 2 CRH receptors attenuated the accompanying elevation of corticosterone levels. These data indicate that the suppression of the GnRH pulse generator by acute systemic stress requires hypothalamic NKB/NK3R signaling and that any involvement of CRH therewith is functionally upstream of NKB.
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Affiliation(s)
- P Grachev
- Division of Women's Health (P.G., X.F.L., M.H.H., S.Y.L., K.T.O.), School of Medicine, King's College London, United Kingdom; Mammal Research Institute (R.P.M.), University of Pretoria, Pretoria, South Africa; Medical Research Council Receptor Biology Unit, University of Cape Town, Cape Town, South Africa; Centre for Integrative Physiology, University of Edinburgh, Scotland; and Henry Wellcome Laboratory for Integrative Neuroscience & Endocrinology (S.L.L.), University of Bristol, Bristol, United Kingdom
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KUWAHARA-OTANI S, MAEDA S, TANAKA K, HAYAKAWA T, SEKI M. Systemic Administration of Lipopolysaccharide Increases the Expression of Aquaporin-4 in the Rat Anterior Pituitary Gland. J Vet Med Sci 2013; 75:1081-4. [DOI: 10.1292/jvms.13-0083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Sachi KUWAHARA-OTANI
- Department of Anatomy and Cell Biology, Hyogo College of Medicine, 1–1 Mukogawa-cho, Nishinomiya, Hyogo 663–8501, Japan
| | - Seishi MAEDA
- Department of Anatomy and Cell Biology, Hyogo College of Medicine, 1–1 Mukogawa-cho, Nishinomiya, Hyogo 663–8501, Japan
| | - Koichi TANAKA
- Department of Anatomy and Cell Biology, Hyogo College of Medicine, 1–1 Mukogawa-cho, Nishinomiya, Hyogo 663–8501, Japan
| | - Tetsu HAYAKAWA
- Department of Anatomy and Cell Biology, Hyogo College of Medicine, 1–1 Mukogawa-cho, Nishinomiya, Hyogo 663–8501, Japan
| | - Makoto SEKI
- Department of Anatomy and Cell Biology, Hyogo College of Medicine, 1–1 Mukogawa-cho, Nishinomiya, Hyogo 663–8501, Japan
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Signaling of cytokines is important in regulation of GnRH neurons. Mol Neurobiol 2011; 45:119-25. [PMID: 22161498 DOI: 10.1007/s12035-011-8224-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 12/05/2011] [Indexed: 01/17/2023]
Abstract
Cytokines encompass a broad class of peptides that mediate signals in a broad range of physiological situations including inflammation, infection, and obesity. The cytokine receptor-associated tyrosine kinase, Jak2, is one of the most important proteins mediating cytokine signaling pathway activation. Recently, our group has demonstrated that Jak2 signaling in the gonadotropin-releasing hormone (GnRH) neuron plays a critical role in fertility in males and females, implicating cytokine activation of the neuron in GnRH neuronal development and function. To date, the specific cytokine(s) essential for activating Jak2 during neuroendocrine development are not known. In this article, we review the evidence for the role of several class 1 cytokines in regulating GnRH neuronal development, GnRH secretion, and GnRH expression.
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Li XF, Knox AMI, O'Byrne KT. Corticotrophin-releasing factor and stress-induced inhibition of the gonadotrophin-releasing hormone pulse generator in the female. Brain Res 2010; 1364:153-63. [PMID: 20727865 DOI: 10.1016/j.brainres.2010.08.036] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2010] [Revised: 08/09/2010] [Accepted: 08/12/2010] [Indexed: 10/19/2022]
Abstract
It is well established that stress activates the hypothalamo-pituitary-adrenal (HPA) axis and suppresses the hypothalamo-pituitary-gonadal (HPG) axis. A large literature dealing with various stressors that regulate gonadotrophin-releasing hormone (GnRH) secretion in a variety of species (including nonhuman primates, sheep, and rats) provides evidence that stress modulates GnRH secretion by activating the corticotrophin-releasing factor (CRF) system and sympathoadrenal pathways, as well as the limbic brain. Different stressors may suppress the HPG axis by activating or inhibiting various pathways in the CNS. In addition to CRF being the principal hypophysiotropic factor driving the HPA axis, it is a potent inhibitor of the GnRH pulse generator. The suppression of the GnRH pulse generator by a variety of stressful stimuli can be blocked by CRF antagonists, suggesting a pivotal role for endogenous CRF. The differential roles for CRF receptor type 1 (CRF-R1) and CRF-R2 in stress-induced suppression of the GnRH pulse generator add to the complexity of CRF regulation of the HPG axis. Although the precise sites and mechanisms of action remain to be elucidated, noradrenergic and gamma-amino-butyric acid (GABA) neurones are implicated in the system's regulation, and opioids and kisspeptin in the medial preoptic area (mPOA) and hypothalamic arcuate nucleus (ARC) may operate downstream of the CRF neuronal system.
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Affiliation(s)
- X F Li
- Division of Reproduction and Endocrinology, King's College London, Guy's Campus, SE1 1UL, UK
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17
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Iwasa T, Matsuzaki T, Murakami M, Kinouchi R, Ogata R, Kuwahara A, Yasui T, Irahara M. Neonatal lipopolysaccharide exposure attenuates the homotypic stress-induced suppression of LH secretion in adulthood in male rat. Int J Dev Neurosci 2009; 27:345-9. [PMID: 19460628 DOI: 10.1016/j.ijdevneu.2009.03.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 02/26/2009] [Accepted: 03/06/2009] [Indexed: 01/11/2023] Open
Abstract
Neonatal immune challenges have a long-lasting influence on immune response. Using male Sprague-Dawley rats, we examined whether neonatal lipopolysaccharide (LPS) challenge alters the sensitivity of male reproductive function to adult LPS challenge and at which level (central or testes) the alteration occurs. We also examined the mRNA expression of proinflammatory cytokines in the hypothalamus and testes because they have a pivotal role in immune stress-induced suppression of gonadotropin secretion and testosterone synthesis. On day 10 after birth, all the pups were injected with LPS (100 microg/kg, i.p.) or saline. Thereafter, LPS (100 microg/kg, i.p.) or saline was injected in adulthood at 8 weeks of age. The serum LH concentration was decreased by LPS injection during adulthood in the neonatal saline-injected rats. This suppressive effect was not seen in the neonatal LPS-injected rats. The serum testosterone concentration was decreased by adult LPS injection in both the neonatal LPS-injected and neonatal saline-injected rats. The expression levels of KiSS-1, which encodes kisspeptin, known to have a crucial role in the regulation of gonadotropin secretion, and GnRH mRNA in the hypothalamus and LHbeta mRNA in the pituitary were not influenced by neonatal or adult LPS injection. On the other hand, the expression levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) mRNA in the hypothalamus and testes were increased by adult LPS injection in both the neonatal LPS-injected and neonatal saline-injected rats. Furthermore, the expression levels of these factors in the hypothalamus after adult LPS injection were significantly lower in the neonatal LPS-injected rats than in the neonatal saline-injected rats. These findings indicate that neonatal LPS challenge reduces the sensitivity of male reproductive function to the suppressive effects of LPS, mainly at the central level. Attenuation of proinflammatory cytokine synthesis in the hypothalamus might be involved in this alteration.
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Affiliation(s)
- Takeshi Iwasa
- Department of Obstetrics and Gynecology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
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18
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Wagenmaker ER, Breen KM, Oakley AE, Tilbrook AJ, Karsch FJ. Psychosocial stress inhibits amplitude of gonadotropin-releasing hormone pulses independent of cortisol action on the type II glucocorticoid receptor. Endocrinology 2009; 150:762-9. [PMID: 18832098 PMCID: PMC2646534 DOI: 10.1210/en.2008-0757] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Our laboratory has developed a paradigm of psychosocial stress (sequential layering of isolation, blindfold, and predator cues) that robustly elevates cortisol secretion and decreases LH pulse amplitude in ovariectomized ewes. This decrease in LH pulse amplitude is due, at least in part, to a reduction in pituitary responsiveness to GnRH, caused by cortisol acting via the type II glucocorticoid receptor (GR). The first experiment of the current study aimed to determine whether this layered psychosocial stress also inhibits pulsatile GnRH release into pituitary portal blood. The stress paradigm significantly reduced GnRH pulse amplitude compared with nonstressed ovariectomized ewes. The second experiment tested if this stress-induced decrease in GnRH pulse amplitude is mediated by cortisol action on the type II GR. Ovariectomized ewes were allocated to three groups: nonstress control, stress, and stress plus the type II GR antagonist RU486. The layered psychosocial stress paradigm decreased GnRH and LH pulse amplitude compared with nonstress controls. Importantly, the stress also lowered GnRH pulse amplitude to a comparable extent in ewes in which cortisol action via the type II GR was antagonized. Therefore, we conclude that psychosocial stress reduces the amplitude of GnRH pulses independent of cortisol action on the type II GR. The present findings, combined with our recent observations, suggest that the mechanisms by which psychosocial stress inhibits reproductive neuroendocrine activity at the hypothalamic and pituitary levels are fundamentally different.
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Affiliation(s)
- Elizabeth R Wagenmaker
- Department of Molecular and Integrative Physiology and Reproductive Sciences Program, University of Michigan, Ann Arbor, MI 48109-5622, USA
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19
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Kinsey-Jones JS, Li XF, Knox AMI, Wilkinson ES, Zhu XL, Chaudhary AA, Milligan SR, Lightman SL, O'Byrne KT. Down-regulation of hypothalamic kisspeptin and its receptor, Kiss1r, mRNA expression is associated with stress-induced suppression of luteinising hormone secretion in the female rat. J Neuroendocrinol 2009; 21:20-9. [PMID: 19094090 DOI: 10.1111/j.1365-2826.2008.01807.x] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Identification of kisspeptin (Kiss1) and its G protein-coupled receptor 54 (Kiss1r) as an essential component of the hypothalamic-pituitary-gonadal (HPG) axis controlling gonadotrophin secretion raises the possibility that kisspeptin-Kiss1r signalling may play a critical role in the transduction of stress-induced suppression of reproduction. We examined the effects of: (i) three different stressors, known to suppress pulsatile luteinising hormone (LH) secretion; (ii) corticotrophin-releasing factor (CRF); and (iii) corticosterone on Kiss1 and Kiss1r expression in key hypothalamic sites regulating gonadotrophin secretion: the medial preoptic area (mPOA) and arcuate nucleus (ARC). Ovariectomised oestrogen-replaced rats were implanted with i.v., subcutaneous or i.c.v. cannulae. Blood samples were collected at 5-min intervals for 5-6 h for detection of LH. Quantitative reverse transcriptase-polymerase chain reaction was used to determine Kiss1 and Kiss1r mRNA levels in brain punches of the mPOA and ARC collected 6 h after restraint, insulin-induced hypoglycaemia or lipopolysaccharide stress, or after i.c.v. administration of CRF, or acute or chronic subcutaneous administration of corticosterone. We observed down-regulation of at least one component of the kisspeptin-Kiss1r signalling system by each of the stress paradigms within the mPOA and ARC. CRF decreased Kiss1 and Kiss1r expression in both the mPOA and ARC. Both acute and chronic stress levels of corticosterone resulted in a concomitant decrease in Kiss1 and an increase in kiss1r mRNA expression in the mPOA and ARC. This differential regulation of Kiss1 and Kiss1r might account for the lack of effect corticosterone has on pulsatile LH secretion. Considering the pivotal role for kisspeptin-Kiss1r signalling in the control of the HPG axis, these results suggest that the reduced Kiss1-Kiss1r expression may be a contributing factor in stress-related suppression of LH secretion.
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Affiliation(s)
- J S Kinsey-Jones
- Division of Reproduction and Endocrinology, King's College London, Guy's Campus, UK
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20
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Whitlock BK, Daniel JA, Wilborn RR, Elsasser TH, Carroll JA, Sartin JL. Comparative aspects of the endotoxin- and cytokine-induced endocrine cascade influencing neuroendocrine control of growth and reproduction in farm animals. Reprod Domest Anim 2008; 43 Suppl 2:317-23. [PMID: 18638141 DOI: 10.1111/j.1439-0531.2008.01180.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Disease in animals is a well-known inhibitor of growth and reproduction. Earlier studies were initiated to determine the effects of endotoxin on pituitary hormone secretion. These studies found that in sheep, growth hormone (GH) concentration was elevated, whereas insulin-like growth factor-I (IGF-I) was inhibited, as was luteinizing hormone (LH). Examination of the site of action of endotoxin in sheep determined that somatotropes expressed the endotoxin receptor (CD14) and that both endotoxin and interleukin-I beta activated GH secretion directly from the pituitary. In the face of elevated GH, there is a reduction of IGF-I in all species examined. As GH cannot activate IGF-I release during disease, there appears to be a downregulation of GH signalling at the liver, perhaps related to altered nitration of Janus kinase (JAK). In contrast to GH downregulation, LH release is inhibited at the level of the hypothalamus. New insights have been gained in determining the mechanisms by which disease perturbs growth and reproduction, particularly with regard to nitration of critical control pathways, with this perhaps serving as a novel mechanism central to lipopolysaccharide suppression of all signalling pathways. This pathway-based analysis is critical to the developing novel strategies to reverse the detrimental effect of disease on animal production.
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Affiliation(s)
- B K Whitlock
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA
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21
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Profound effects of burn and ethanol on proinflammatory cytokines of the reproductive axis in the male mouse. J Burn Care Res 2008; 29:531-40. [PMID: 18388566 DOI: 10.1097/bcr.0b013e3181711273] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Thermal injury is often associated with previous ethanol exposure, and close to 50% of patients admitted to a burn unit have a potentially high blood ethanol level. Cellular mechanisms by which ethanol and/or burn affect the hypothalamic-pituitary-gonadal (HPG) axis are not entirely understood. However, it is known that the proinflammatory cytokines, tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 influence negatively on the endocrine functions of the HPG. We report a time course study (6, 12, 24, and 48 hours) of the effects of ethanol, burn, or the combination of burn/ethanol on proinflammatory cytokines of the hypothalamus, pituitary and testes of male C57Bl/6 mice. We found that there were highly significant increases in each of these cytokines caused by ethanol, burn, and burn/ethanol compared with sham/vehicle (P < .001). This was true in hypothalamus, pituitary, and testes. Because these cytokines generally reduce reproductive function, it may be that proinflammatory cytokines of HPG axis mediate the deleterious effects of burn and/or ethanol on mammalian reproduction.
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22
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Zhu Q, Emanuele MA, LaPaglia N, Kovacs EJ, Emanuele NV. Vitamin E prevents ethanol-induced inflammatory, hormonal, and cytotoxic changes in reproductive tissues. Endocrine 2007; 32:59-68. [PMID: 17992603 DOI: 10.1007/s12020-007-9010-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Revised: 09/11/2007] [Accepted: 09/11/2007] [Indexed: 12/01/2022]
Abstract
Ethanol causes decreased function of the hypothalamic-pituitary-gonadal (HPG) axis. Ethanol resulted in inflammatory changes in HPG manifested by increased concentrations of pro-inflammatory cytokines. Since, such cytokines have deleterious effects on functions of HPG, it seemed possible that ethanol's suppressive action could be due, at least in part, to this inflammation. Since oxidative stress can cause inflammation, we have used the antioxidant vitamin E to test, whether reducing inflammation might protect reproductive functions from ethanol. Rats were fed an ethanol diet or pair fed identically without ethanol for a 3-week period. For the last 10 days, animals were given 30 IU/kg or 90 IU/kg or vehicle. Ethanol significantly increased hypothalamic, pituitary and testicular TNF-alpha and IL-6, all changes prevented by the higher dose of vitamin E. Also, ethanol induced changes in LHRH, LH, testosterone, and testicular germ cell apoptosis were similarly prevented by vitamin E. These data strikingly show that vitamin E protects the HPG from deleterious effects of ethanol and suggests that the mechanism of this protection might be both anti-inflammatory and antioxidant.
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Affiliation(s)
- Qianlong Zhu
- Burn and Shock Trauma Institute, Loyola University Medical Center, Maywood, IL 60153, USA
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23
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Jain A, Polotsky AJ, Rochester D, Berga SL, Loucks T, Zeitlian G, Gibbs K, Polotsky HN, Feng S, Isaac B, Santoro N. Pulsatile luteinizing hormone amplitude and progesterone metabolite excretion are reduced in obese women. J Clin Endocrinol Metab 2007; 92:2468-73. [PMID: 17440019 DOI: 10.1210/jc.2006-2274] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Female obesity is linked to abnormal menstrual cycles, infertility, reproductive wastage, and deficient LH, FSH, and progesterone secretion. OBJECTIVE AND DESIGN To elucidate the reproductive defects associated with obesity, we sampled 18 eumenorrheic (nonpolycystic ovary syndrome) women with a mean +/- sem body mass index of 48.6 +/- 1.4 kg/m2 with daily, first morning voided urine collections, seven of whom also had early follicular phase 12-h, every 10-min blood sampling to assess LH pulses. Daily hormones were compared with 11 eumenorrheic, normal-weight controls. A separate control group of 12 eumenorrheic, normal-weight women was used for the LH pulse studies. MAIN OUTCOME MEASURES Assays for LH (serum and urine) and FSH, and estradiol and progesterone metabolites (estrone conjugate and pregnanediol glucuronide; urine) were performed. Daily hormones were meaned and normalized to a 28-d cycle length. LH pulsations were determined using two objective methods. Group means were compared using t tests. RESULTS Reduced whole-cycle mean, normalized pregnanediol glucuronide was observed in obese (38.2 +/- 2.1 microg/mg creatine) compared with normal-weight women (181.3 +/- 35.1 microg/mg creatine; P = 0.002), without significant differences in LH, FSH, or estrone conjugate. Early follicular phase LH pulse frequency did not differ from normal-weight women, but both amplitude and mean LH were dramatically reduced in obese women (0.8 +/- 0.1 and 2.0 +/- 0.3 IU/liter) compared with controls (1.6 +/- 0.2 and 3.4 +/- 0.2 IU/liter; P < 0.01). CONCLUSIONS A novel defect in the amplitude but not the frequency of LH pulsations appears to underlie the reproductive phenotype of obesity. The deficit in pregnanediol glucuronide appears to exceed the deficit in LH. The patterns of hypothalamic-pituitary-ovarian axis function unique to the obese state differ from other abnormal reproductive states.
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Affiliation(s)
- Akas Jain
- Department of Obstetrics, Gynecology, and Women's Health, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
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24
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Fernandez-Solari J, Prestifilippo JP, Bornstein SR, McCann SM, Rettori V. Participation of the endocannabinoid system in the effect of TNF-alpha on hypothalamic release of gonadotropin-releasing hormone. Ann N Y Acad Sci 2007; 1088:238-50. [PMID: 17192570 DOI: 10.1196/annals.1366.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
It is known that Delta(9)-tetrahydrocannabinol (THC), the major active ingredient of marijuana, can suppress reproductive function. Also, we reported previously that the endocannabinoid, anandamide (AEA), inhibited gonadotropin-releasing hormone (LHRH) release from medial basal hypothalamus (MBH) of male rats incubated in vitro as well as reduced plasma LH levels after i.c.v. AEA injections into the cerebral lateral ventricle. On the other hand, it is known that during endotoxemia the hypothalamic gonadotropin axis is inhibited. Therefore, the aim of the present study was to determine whether the effect of TNF-alpha, a proinflammatory cytokine induced by lipopolysaccharide (LPS) that inhibits LHRH release, is mediated by the activation of the endocannabinoid system. The intraperitoneal injection of LPS (5 mg/kg) as well as the i.c.v. injection of tumor necrosis factor-alpha (TNF-alpha) (100 ng/rat) increased significantly the AEA synthesis measured ex vivo in MBHs removed 3 h after the treatments. To examine the possibility that TNF-alpha also acted by increasing the synthesis of AEA that was released and activated the CB1-r followed by inhibition of LHRH release, we measured the effect of TNF-alpha on the AEA synthase activity in MBHs incubated in vitro. As expected, we found that TNF-alpha (2.9 x 10(-9) M) increased the AEA synthesis. Second, we showed that TNF-alpha reduced significantly the forskolin-stimulated LHRH release and that the CB1-r antagonist AM251 (10(-5) M) blocked that inhibition, supporting the hypothesis that TNF-alpha inhibits LHRH release, acting at least in part by activating the endocannabinoid system. Therefore, our data demonstrate a key role for the endocannabinoid system in the response of the reproductive system to inflammatory signals.
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Affiliation(s)
- Javier Fernandez-Solari
- Centro de Estudios Farmacológicos y Botánicos, Consejo Nacional de Investigaciones Cientificas y Técnicas, Buenos Aires, Argentina
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25
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Xiao E, Xia-Zhang L, Vulliemoz N, Rivier J, Ferin M. Astressin B, a corticotropin-releasing hormone receptor antagonist, accelerates the return to normal luteal function after an inflammatory-like stress challenge in the rhesus monkey. Endocrinology 2007; 148:841-8. [PMID: 17082255 DOI: 10.1210/en.2006-1074] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Endogenous release of CRH in stress has been associated with a dysfunctional reproductive endocrine axis. In the rhesus monkey, an inflammatory-like stress challenge in the luteal phase decreases luteal secretory function. Here, we tested the effectiveness of astressin B, a nonspecific CRH receptor antagonist, in constraining the deleterious impact of a 10-d lipopolysaccharide (LPS) challenge on the menstrual cycle. Two protocols were carried out in nine animals. In the first, the animals, after showing two normal consecutive control cycles, were injected daily for 10 days with LPS (75-125 mug/d) during the luteal phase of the cycle. The animals were followed through the two postchallenge cycles. The second protocol, carried out in the following year, was identical with protocol 1, except that the animals were treated with astressin B (0.45 mg/kg) 1 h before each daily LPS challenge during the luteal phase. Blood samples were obtained daily to document cyclic hormones levels. The LPS challenge significantly decreased luteal progesterone and LH release during the challenge cycle. Inhibition of luteal progesterone extended to the two successive postchallenge cycles. Astressin B treatment prevented luteal LH but not luteal progesterone decrease during the treatment cycle and restored normal progesterone secretion during the two posttreatment cycles. We conclude that the deleterious impact of a short-term inflammatory stress challenge on luteal function is far longer than the stress period itself. Systemic administration of astressin B accelerates the return to normal luteal function, presumably by restoring normal neuroendocrine regulation of gonadotropin secretion.
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Affiliation(s)
- Ennian Xiao
- Department of Obstetrics and Gynecology, Columbia University, College of Physicians and Surgeons, 630 West 168th Street, New York, New York 10032, USA
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26
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Rettori V, Fernandez-Solari J, Prestifilippo JP, Mohn C, De Laurentiis A, Bornstein SR, Ehrhart-Bornstein M, Elverdin JC, McCann SM. Endocannabinoids in TNF-alpha and ethanol actions. Neuroimmunomodulation 2007; 14:188-92. [PMID: 18073513 DOI: 10.1159/000110645] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
During marijuana and alcohol consumption as well as during inflammation the reproductive axis is inhibited, mainly through the inhibition of luteinizing hormone-releasing hormone release. In male rats, this inhibitory effect is mediated, at least in part, by the activation of hypothalamic cannabinoid type 1 receptors (CB1). During inflammation, this activation of the endocannabinoid system seems to be mediated by an increase in TNF-alpha production followed by anandamide augmentations, similarly the effect of intragastric administration of ethanol (3 g/kg) seems to be due to an increase in anandamide. On the other hand, a number of different actions mediated by the endocannabinoid system in various organs and tissues have been described. Both cannabinoid receptors, CB1 and CB2, are localized in the submandibular gland where they mediate the inhibitory effect of intrasubmandibular injections of the endocannabinoid anandamide (6 x 10(-5)M) on salivary secretion. Lipopolysaccharide (5 mg/kg/3 h) injected intraperitoneally and ethanol (3 g/kg/1 h) injected intragastrically inhibited the salivary secretion induced by the sialogogue metacholine; this inhibitory effect was blocked by CB1 and/or CB2 receptor antagonists. Similar to the hypothalamus, these effects seem to be mediated by increased anandamide. In summary, similar mechanisms mediate the inhibitory actions of endocannabinoids and cannabinoids in both hypothalamus and submandibular gland during drug consumption and inflammation.
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Affiliation(s)
- Valeria Rettori
- Centro de Estudios Farmacológicos y Botánicos, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Buenos Aires, Argentina.
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27
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Matsuwaki T, Kayasuga Y, Yamanouchi K, Nishihara M. Maintenance of gonadotropin secretion by glucocorticoids under stress conditions through the inhibition of prostaglandin synthesis in the brain. Endocrinology 2006; 147:1087-93. [PMID: 16293664 DOI: 10.1210/en.2005-1056] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have previously reported that glucocorticoids counteract the suppressive effects of tumor necrosis factor-alpha on both pulsatile and surge secretion of LH. This suggests that glucocorticoids have a protective effect on reproductive function under infectious stress. In the present study, we examined whether glucocorticoids maintain pulsatile LH secretion under various conditions of acute stress and the possible involvement of prostaglandins (PGs) in glucocorticoid actions. Three different types of stressors, namely infectious (lipopolysaccharide, 0.5 microg/kg), hypoglycemic (2-deoxy-D-glucose, 100 mg/kg), and restraint stress (1 h) were applied to ovariectomized rats. In ovariectomized rats, LH pulses were partially suppressed by restraint, but not by lipopolysaccharide or 2-deoxy-D-glucose. On the other hand, adrenalectomy (ADX) significantly enhanced the suppressive effects of all the stressors applied on LH pulses. Treatment with both corticosterone (25 mg/kg) and indomethacin (10 mg/kg) in ADX rats significantly attenuated the suppressive effects of these stressors on LH pulses. In addition, the immunoreactivity of cyclooxygenase-2, a PG-synthesizing enzyme, in the brain under stress conditions was much enhanced by ADX, and this was counteracted by corticosterone treatment. Similarly, an increase in body temperature under restraint stress was enhanced by ADX and suppressed by corticosterone. These results suggest that suppression of LH pulsatility by stress is mediated by PGs in the brain, and that increased release of endogenous glucocorticoids in response to stress counteracts this suppression by inhibiting PG synthesis, and thereby maintains reproductive function regardless of the nature of the stressor.
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Affiliation(s)
- Takashi Matsuwaki
- Department of Veterinary Physiology, Veterinary Medical Science, University of Tokyo, Tokyo 113-8657, Japan
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Akema T, He D, Sugiyama H. Lipopolysaccharide increases gamma-aminobutyric acid synthesis in medial preoptic neurones in association with inhibition of steroid-induced luteinising hormone surge in female rats. J Neuroendocrinol 2005; 17:672-8. [PMID: 16159380 DOI: 10.1111/j.1365-2826.2005.01358.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lipopolysaccharide (LPS), an endotoxin produced by gram-negative bacteria, inhibits gonadotrophin secretion and ovulation in female mammals. The present study was undertaken to examine whether gamma-aminobutyric acid (GABA)-synthesising neurones in the medial preoptic area (mPOA) may be involved in the inhibition by LPS of progesterone-induced luteinising hormone (LH) surge in ovariectomised oestrogen-primed rats. An intravenous injection of LPS (10 microg) at noon significantly increased the content of glutamic acid decarboxylase 67 (GAD67), a GABA-synthesising enzyme, in brain tissues including the mPOA. LPS treatment also significantly increased the number of detectable GAD67-immunoreactive (ir) as well as GABA-ir cells in the mPOA, compared to control rats. The same LPS challenge completely eliminated the steroid-induced LH surge, which was normally induced in control rats in the afternoon. A local injection of muscimol (100 ng), a GABA(A) receptor agonist, into the mPOA also significantly attenuated the LH surge, mimicking the effect of LPS. These results suggest that LPS stimulates GABA synthesis in preoptic neurones, which in turn inhibit the LH surge in female rats. The results also support the hypothesis that diminution of the GABAergic suppressive activity in the mPOA permits the LH surge to be induced.
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Affiliation(s)
- T Akema
- Department of Physiology, St Marianna University School of Medicine, Kawasaki, Japan.
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He D, Akema T. Inhibition by lipopolysaccharide of naloxone-induced luteinising hormone secretion is accompanied by increases in corticotropin-releasing factor immunoreactivity in hypothalamic paraventricular neurones in female rats. J Neuroendocrinol 2005; 17:67-72. [PMID: 15796756 DOI: 10.1111/j.1365-2826.2005.01275.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have recently reported that lipopolysaccharide (LPS), a bacterial endotoxin, inhibits steroid-induced as well as naloxone-induced luteinising hormone (LH) secretion in ovariectomised oestrogen-primed rats. In the present study, we examined whether corticotropin-releasing factor (CRF) may be involved in the LPS-induced inhibition of LH secretion. Unanaesthetised rats were treated with an intravenous (i.v.) injection of LPS (10 microg) or saline, followed by an i.v. injection of naloxone (20 mg/kg). After sequential blood samples were collected for determination of serum LH concentrations, the brains were fixed and CRF-immunoreactivity was examined histochemically. In control rats receiving saline injections, only a small number of CRF-immunoreactive (ir) cells were found in the parvocellular portion of the hypothalamic paraventricular nucleus (PVN), and naloxone significantly increased serum LH concentrations within 10 min. By contrast, in LPS-treated rats, the number of CRF-ir cells was significantly greater than that in control rats, and the effect of naloxone was completely abolished. In a separate experiment, an intracerebroventricular injection of 5 microg CRF inhibited naloxone-induced LH release, mimicking the effect of LPS. These results suggest that LPS stimulates production of CRF in PVN neurones, which in turn inhibits LH secretion without opioidergic mediation.
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Affiliation(s)
- D He
- Department of Physiology, St Mariana University School of Medicine, Kawasaki, Japan
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Emanuele N, LaPaglia N, Kovacs EJ, Emanuele MA. Effects of chronic ethanol (EtOH) administration on pro-inflammatory cytokines of the hypothalamic-pituitary-gonadal (HPG) axis in female rats. Endocr Res 2005; 31:9-16. [PMID: 16238187 DOI: 10.1080/07435800500228930] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We and others have investigated the effects of acute and chronic ethanol (EtOH) administration on function of the hypothalamic-pituitary-gonadal (HPG) axis in female rats, consistently finding EtOH to be detrimental. There are now substantial data that pro-inflammatory cytokines, such as tumor necrosis factor alpha (TNFalpha) and interleukin 6 (IL-6), have anti-reproductive effects. If EtOH increased levels of these cytokines, such data would be consistent with, though not necessarily prove, a cytokine mediated mechanism for EtOH's deleterious effects on reproduction. Young adult female Sprague Dawley rats were used. In the experiment reported here, the Lieber DeCarli diet was used, with animals fed a 36% EtOH containing diet or pair fed an identical diet which contained dextrimaltose instead of EtOH. This was done for 4 to 6 weeks. TNFalpha and IL-6 were measured in the hypothalamus, pituitary, and ovary by ELISA. EtOH exposure resulted in significant increases in TNFalpha and IL-6 in hypothalami, pituitaries, and ovaries. The data reported here are the first to show consistent stimulatory effects of EtOH exposure on cytokines in the reproductive axis of female rats. Because the effects of these cytokines are generally anti-reproductive, these data provide a rational for more rigorous testing of the notion that part of EtOH's deleterious HPG effects may be due to such immuno-endocrine interactions.
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Affiliation(s)
- Nicholas Emanuele
- Department of Medicine, Burn and Shock Trauma Institute, Research and Medical Services, VA Hospital, Hines, Illinois, USA.
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31
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Watanobe H, Hayakawa Y. Hypothalamic interleukin-1 beta and tumor necrosis factor-alpha, but not interleukin-6, mediate the endotoxin-induced suppression of the reproductive axis in rats. Endocrinology 2003; 144:4868-75. [PMID: 12960020 DOI: 10.1210/en.2003-0644] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It is well established that endotoxemia disrupts reproductive capability, and several proinflammatory cytokines, especially IL-1 beta, IL-6, and TNF-alpha in the brain, have been implicated in this endocrine aberration. However, no previous study has directly compared the effects of the three major proinflammatory cytokines (IL-1 beta, IL-6, and TNF-alpha) on the in vivo release of hypothalamic GnRH, a secretagogue of LH from the pituitary. Therefore, in this study, we addressed this issue with two complementary approaches involving push-pull perfusion in freely moving ovariectomized female rats. First, we examined the effects of systemic lipopolysaccharide (LPS) treatment on the release of plasma LH, and of GnRH, IL-1 beta, IL-6, and TNF-alpha in the hypothalamic medial preoptic area (MPOA), where the majority of GnRH neuronal perikarya are located. LPS inhibited the secretion of both LH and GnRH and concomitantly stimulated the release of all three cytokines. We next tested the effects of direct MPOA perfusion with the respective cytokines (at three different concentrations each) on the GnRH and LH secretion. IL-1 beta and TNF-alpha, at the concentrations that were observed in the MPOA after the LPS injection, were equipotent in inhibiting the GnRH-LH system, whereas IL-6 was ineffective (even at a supraphysiological concentration). These results strongly suggest that IL-1 beta and TNF-alpha may represent the major proinflammatory cytokines mediating the LPS-induced suppression of GnRH and LH release, whereas the role of IL-6 seems to be insignificant.
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Affiliation(s)
- Hajime Watanobe
- Division of Internal Medicine, Clinical Research Center, International University of Health and Welfare, 2600-1 Kitakanemaru, Otawara, Tochigi 324-8501, Japan.
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Matsuwaki T, Watanabe E, Suzuki M, Yamanouchi K, Nishihara M. Glucocorticoid maintains pulsatile aecretion of luteinizing hormone under infectious stress condition. Endocrinology 2003; 144:3477-82. [PMID: 12865328 DOI: 10.1210/en.2002-221111] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have previously shown that TNF-alpha, a major proinflammatory cytokine, suppressed hypothalamic GnRH pulse generator activity and that this inhibitory effect was enhanced by alpha-helical CRH, a CRH receptor antagonist. The present study was conducted to elucidate the involvement of glucocorticoid (GC) in modulating LH pulses under infectious stress condition. Adrenalectomy (ADX) markedly enhanced the suppressive effect of TNF-alpha (1 micro g), injected iv, on LH pulses in ovariectomized (OVX) rats. Pretreatment with a sc injection of corticosterone (10 mg) almost completely restored LH pulses after TNF-alpha injection in OVX/ADX animals. Injection of TNF-alpha increased the number of c-Fos-immunoreactive cells in the supraoptic nucleus (SON), the dorsomedial hypothalamic nucleus (DMH), and the parvocellular region of the paraventricular nucleus (PVN), which was more prominent in OVX/ADX than OVX animals except in the DMH. Pretreatment with corticosterone decreased the number of Fos-immunoreactive cells in the PVN and SON but not in the DMH. These results suggest that GC has a potent protective effect on LH pulsatility under conditions of infectious stress, the mechanism of which involves at least the suppression of the excitability of PVN and SON neurons. In addition, the DMH does not seem to mediate the central action of GC, though it may play an important role in inducing pathophysiological reactions to invasive stress.
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Affiliation(s)
- Takashi Matsuwaki
- Department of Veterinary Physiology, Veterinary Medical Science, The University of Tokyo, Tokyo 113-8657, Japan
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33
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Daniel JA, Abrams MS, deSouza L, Wagner CG, Whitlock BK, Sartin JL. Endotoxin inhibition of luteinizing hormone in sheep. Domest Anim Endocrinol 2003; 25:13-9. [PMID: 12963096 DOI: 10.1016/s0739-7240(03)00042-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Administration of endotoxin suppresses circulating concentration of luteinizing hormone (LH) in a number of species, including rats, sheep, cattle, and non-human primates. Specifically, endotoxin administration decreases circulating concentration of LH and LH pulses frequency in castrated male sheep. Endotoxin could alter circulating concentrations of LH via actions at the hypothalamus through altered GnRH production and/or release, or endotoxin could alter circulating concentrations of LH at the level of the pituitary via inhibition of LH production and release or inhibition of LH in response to GnRH. The site of endotoxin suppression of circulating concentrations of LH as well as possible mediators of endotoxin suppression of circulating concentrations of LH, including cortiocotropin-releasing hormone, arginine vasopressin, glucocorticoids, inflammatory cytokines, prostaglandins, and opioids, are discussed.
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Affiliation(s)
- J A Daniel
- Animal and Range Science Department, South Dakota State University, Brookings, SD 57007, USA
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He D, Sato I, Kimura F, Akema T. Lipopolysaccharide inhibits luteinizing hormone release through interaction with opioid and excitatory amino acid inputs to gonadotropin-releasing hormone neurones in female rats: possible evidence for a common mechanism involved in infection and immobilization stress. J Neuroendocrinol 2003; 15:559-63. [PMID: 12716406 DOI: 10.1046/j.1365-2826.2003.01031.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Acute immobilization stress suppresses naloxone- and N-methyl-d-aspartate (NMDA)-induced, but not gonadotropin-releasing hormone (GnRH)-induced, luteinizing hormone (LH) release in ovariectomized oestrogen-primed rats. To explore whether a common mechanism may underlie inhibition of gonadotropin secretion by various stressors, we examined in the present study the effect of lipopolysaccharide (LPS) on LH release induced by progesterone, GnRH, naloxone and NMDA. The effect of LPS on Fos expression in GnRH neurones was also examined in association with its effect on steroid-induced LH release. Injection of progesterone (1 mg/rat) at noon induced an LH surge in the afternoon in ovariectomized rats pretreated with oestradiol benzoate. In these rats, the majority of hypothalamic GnRH neurones expressed Fos in the evening. Intravenous (i.v.) administration of LPS (10 micro g/rat) inhibited steroid-induced LH release and also reduced the Fos expression in GnRH neurones. In separate experiments, an i.v. injection of GnRH (50 ng/kg), naloxone (10 mg/kg) or NMDA (20 mg/kg) significantly elevated serum LH concentrations within 10 min. Pretreatment with LPS, which did not affect basal LH release or GnRH-induced LH release, inhibited naloxone-induced and NMDA-induced LH release. These results show that LPS has a suprapituitary site(s) of action to suppress the activity of GnRH neurones in female rats, and suggest that LPS affects the opioid, as well as the excitatory amino acidergic regulation of GnRH neurones. The similarity of effects of LPS and immobilization stress further suggests that a common mechanism is involved in inhibition of GnRH neurones by different stressors.
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Affiliation(s)
- D He
- Department of Physiology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki 216-8511, Japan
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El-Haj T, Poole S, Farthing MJG, Ballinger AB. Anorexia in a rat model of colitis: interaction of interleukin-1 and hypothalamic serotonin. Brain Res 2002; 927:1-7. [PMID: 11814426 DOI: 10.1016/s0006-8993(01)03305-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND AND AIMS Anorexia induced by experimental colitis in rats is mediated, in part, by increased release of serotonin (5-HT) from the hypothalamic paraventricular nucleus (PVN). In this model, anorexia is attenuated by treatment with an interleukin-1 (IL)-1 receptor antagonist (ra). However, a functional link between central IL-1 receptors and 5-HT release remains unproven. We have tested the hypothesis that anorexia associated with experimental colitis is mediated by IL-1 induced release of 5-HT. METHODS In vivo 5-HT release in the PVN was measured in rats with 2,4,6-trinitrobenzenesulphonic acid (TNBS)-induced colitis, treated with intracerebroventricular infusion of IL-1ra or vehicle treated controls. The effect of inhibition of tumour necrosis factor-alpha on food intake and PVN 5-HT release in TNBS-colitis was also tested. RESULTS In rats with TNBS-induced colitis, intracerebroventricular infusion of IL-1ra resulted in a 18-fold reduction in PVN 5-HT release compared to vehicle-treated controls. This was associated with a significant increase in food intake in IL-1ra treated rats. In contrast intracerebroventricular administration of anti-tumour necrosis factor antibodies had no effect on either PVN 5-HT release or food intake in rats with TNBS-induced colitis. CONCLUSIONS In animals with TNBS-colitis, anorexia is mediated, in part, by the stimulatory effect of IL-1 on medial hypothalamic 5-HT.
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Affiliation(s)
- Tarek El-Haj
- Department of Adult and Paediatric Gastroenterology, St. Bartholomew's and The Royal London School of Medicine and Dentistry, 2 Newark Street, London E1 2AT, UK
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36
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Naito H, Inoue M, Suzuki Y, Tohei A, Watanabe G, Taya K, Makino J. Ultrasonic vocalization responses in genetically high- and low-emotional rats. Exp Anim 2001; 50:285-91. [PMID: 11515090 DOI: 10.1538/expanim.50.285] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Tsukuba High Emotional (THE) and Tsukuba Low Emotional (TLE) strains of rats have been congenitally bred for use in studies of emotionality. The current study investigated THE and TLE strain differences in the footshock-induced ultrasonic vocalization responses of adult male rats. Ultrasonic vocalization response inducibility (ratio of rats emitting ultrasounds) and vocalization activity in THE rats were statistically higher than in TLE rats. We next examined the causal relation between the ultrasonic vocalizations and the activation of the pituitary-adrenocortical axis in response to footshocks in these two strains of rats. Rats were sorted into two groups, vocalizing and non-vocalizing, after being exposed to the shock regimen daily for 5 successive days. Basal plasma concentrations of ACTH and corticosterone were not different between THE and TLE rats. After receiving footshocks, significant increases in plasma concentrations of ACTH and corticosterone were induced in both strains of rats. These increases in plasma concentrations of ACTH and corticosterone were significantly higher in THE than in TLE rats. However, in vocalizing and non-vocalizing rats of both strains, no statistical differences in plasma concentrations of ACTH and corticosterone were observed after footshocks. These findings suggest that the high emotionality of the adult male rats was reflected in the emission of ultrasounds, and that the emission of ultrasonic vocalizations might not be related to the activation of the pituitary-adrenocortical axis.
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Affiliation(s)
- H Naito
- Department of Neurophysiology, School of Veterinary Medicine, Azabu University, Fuchinobe, Sagamihara 229-8501, Japan
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37
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Harris TG, Battaglia DF, Brown ME, Brown MB, Carlson NE, Viguié C, Williams CY, Karsch FJ. Prostaglandins mediate the endotoxin-induced suppression of pulsatile gonadotropin-releasing hormone and luteinizing hormone secretion in the ewe. Endocrinology 2000; 141:1050-8. [PMID: 10698181 DOI: 10.1210/endo.141.3.7393] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Five experiments were conducted to test the hypothesis that PGs mediate the endotoxin-induced inhibition of pulsatile GnRH and LH secretion in the ewe. Our approach was to test whether the PG synthesis inhibitor, flurbiprofen, could reverse the inhibitory effects of endotoxin on pulsatile LH and GnRH secretion in ovariectomized ewes. Exp 1-4 were cross-over experiments in which ewes received either flurbiprofen or vehicle 2 weeks apart. Jugular blood samples were taken for LH analysis throughout a 9-h experimental period. Depending on the specific purpose of the experiment, flurbiprofen or vehicle was administered after 3.5 h, followed by endotoxin, vehicle, or ovarian steroids (estradiol plus progesterone) at 4 h. In Exp 1, flurbiprofen reversed the endotoxin-induced suppression of mean serum LH concentrations and the elevation of body temperature. In Exp 2, flurbiprofen prevented the endotoxin-induced inhibition of pulsatile LH secretion and stimulation of fever, reduced the stimulation of plasma cortisol and progesterone, but did not affect the rise in circulating tumor necrosis factor-alpha. In Exp 3, flurbiprofen in the absence of endotoxin had no effect on pulsatile LH secretion. In Exp 4, flurbiprofen failed to prevent suppression of pulsatile LH secretion induced by luteal phase levels of the ovarian steroids progesterone and estradiol, which produce a nonimmune suppression of gonadotropin secretion. In Exp 5, flurbiprofen prevented the endotoxin-induced inhibition of pulsatile GnRH release into pituitary portal blood. Our finding that this PG synthesis inhibitor reverses the inhibitory effect of endotoxin leads to the conclusion that PGs mediate the suppressive effects of this immune/inflammatory challenge on pulsatile GnRH and LH secretion.
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Affiliation(s)
- T G Harris
- Department of Physiology, University of Michigan, Ann Arbor 48109-0404, USA
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38
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Sortino MA, Condorelli F, Vancheri C, Canonico PL. Tumor necrosis factor-alpha induces apoptosis in immortalized hypothalamic neurons: involvement of ceramide-generating pathways. Endocrinology 1999; 140:4841-9. [PMID: 10499544 DOI: 10.1210/endo.140.10.7062] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To investigate possible effects that may contribute, together with a direct action on neurohormone secretion, to the impairment of gonadal axis function during inflammation, we evaluated the effect of TNF alpha on the growth and viability of GT1-7 hypothalamic neurons and the intracellular transduction pathways involved in these effects. TNF alpha caused a reduction of cell number and an induction of apoptotic death. These effects were mimicked by cell-permeable analogs of ceramide and by neutral or acidic sphingomyelinase. Exposure to acidic sphingomyelinase induced a persistent (up to 48 h) reduction of cell growth and apoptosis, whereas the effect of neutral sphingomyelinase was time limited. The involvement of acidic sphingomyelinase in TNF alpha action was demonstrated by the partial prevention of ceramide generation, apoptosis, and reduced cell growth by the inhibitor of the acidic sphingomyelinase-generating pathway, D609, whereas the involvement of ceramide was proved by complete prevention of TNF alpha-induced effects by treatment with okadaic acid at concentrations inhibiting ceramide-dependent protein phosphatase. The present data indicate that TNF alpha, through activation of ceramide-generating pathways, is able to affect GT1-7 cell viability, suggesting an additional effect that may contribute to the global action of this cytokine on neuroendocrine activities.
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Affiliation(s)
- M A Sortino
- Institute of Pharmacology, University of Catania School of Medicine, Italy.
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39
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Lackey BR, Gray SL, Henricks DM. The insulin-like growth factor (IGF) system and gonadotropin regulation: actions and interactions. Cytokine Growth Factor Rev 1999; 10:201-17. [PMID: 10647777 DOI: 10.1016/s1359-6101(99)00013-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Insulin-like growth factors (IGF) are polypeptides that regulate growth, differentiation and survival in a multitude of cells and tissues. The IGF system consists of ligands, receptors, binding proteins and binding protein proteases. The influence of the IGF system on reproductive parameters, specifically gonadotropin release and interactions between the IGF system and other effectors of gonadotropin release will be examined in this review.
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Affiliation(s)
- B R Lackey
- Department of Animal and Veterinary Science, Clemson University, SC 29634-0361, USA.
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40
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MohanKumar SM, MohanKumar PS, Quadri SK. Lipopolysaccharide-induced changes in monoamines in specific areas of the brain: blockade by interleukin-1 receptor antagonist. Brain Res 1999; 824:232-7. [PMID: 10196453 DOI: 10.1016/s0006-8993(99)01206-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The purpose of this study was to examine the specificity in the effects of lipopolysaccharide (LPS) on monoamine concentrations in different areas of the brain and the involvement of interleukin-1 (IL-1) in the LPS-induced effects. Adult male rats were injected i.p. with saline, 10 micrograms/kg body weight of LPS, or treated with 250 micrograms of IL-1 receptor antagonist (IL-1ra) 5 min before and 2 h after LPS. Several brain areas including the hippocampus (HI), caudate putamen (CP), the hypothalamic paraventricular nucleus (PVN), arcuate nucleus (AN), median eminence (ME) and the medial preoptic area (MPA) were microdissected and analyzed for neurotransmitter concentrations by HPLC-EC. LPS treatment produced marked increases in the concentrations of norepinephrine (NE), dopamine (DA), serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the PVN. In the AN, it increased DA concentrations and was without any effect on the MPA, ME, CP and HI. Treatment with IL-1ra in combination with LPS completely blocked the LPS-induced effects. It is concluded that LPS produces highly specific changes in monamine metabolism in the hypothalamus and that these effects are mediated at least in part by IL-1beta.
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Affiliation(s)
- S M MohanKumar
- Neuroendocrine Research Laboratory, Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
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41
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Avitsur R, Yirmiya R. Cytokines inhibit sexual behavior in female rats: I. Synergistic effects of tumor necrosis factor alpha and interleukin-1. Brain Behav Immun 1999; 13:14-32. [PMID: 10371675 DOI: 10.1006/brbi.1999.0555] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The secretion of cytokines such as tumor necrosis factor alpha (TNFalpha) and interleukin-1 (IL-1) during immune activation induces sickness behavior. We have previously demonstrated that administration of either lipopolysaccharide (LPS) or IL-1 suppresses sexual behavior in female, but not in male rats. In the present study we sought to determine some of the mechanisms that are involved in mediating the alterations of female sexual behavior during immune activation. We report that sexual motivation of estrous females was reduced by intracerebroventricular administration of either recombinant rat (rr)TNFalpha (7.5 microg/rat) or rrIL-1beta (100 ng/rat), whereas sexual receptivity was altered only by IL-1beta. A significant reduction of both sexual motivation and receptivity was also induced by the combined administration of subthreshold doses of TNFalpha (3 microg/rat) and IL-1beta (20 ng/rat). These findings indicate that TNFalpha and IL-1beta act synergistically to suppress sexual motivation and receptivity. Moreover, LPS (100 microg/kg, ip)-induced reduction of sexual motivation was antagonized by the combined administration of the TNFalpha synthesis blocker pentoxifylline (50 mg/kg, ip) and IL-1 receptor antagonist (10 mg/kg, ip), but not by the administration of each of these substances by itself. In contrast, LPS-induced reduction of sexual receptivity was completely prevented by pentoxifylline. These findings indicate that the effects of LPS on sexual motivation are mediated by the synergistic effects of TNFalpha and IL-1, but only TNFalpha is required for the effect of LPS on receptivity.
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Affiliation(s)
- R Avitsur
- Department of Psychology, The Hebrew University of Jerusalem, Mount Scopus, Jerusalem, 91905, Israel
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42
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Abstract
Systemically administered lipopolysaccharide (LPS) elicits profound changes in pituitary hormone secretion. Pro-inflammatory cytokines have been proposed as mediators of these responses. In this study, we used in-situ hybridization histochemistry to investigate LPS-induced cytokine gene expression in the rat pituitary. After i.p. or i.v. injection of various doses of LPS, mRNA for the immediate-early gene IkappaBu (an inhibitor of NF-kappaB, a transcription factor that regulates the expression of many pro-inflammatory cytokines) was induced in the anterior lobe as early as 0.5 h. The induced IkappaBalpha mRNA expression peaked at 1 h. In the posterior lobe, IkappaBalpha mRNA was first induced at 0.5 h and peaked at 2 h. A similar spatiotemporal pattern of interleukin-1b (IL-1) mRNA induction was observed. In addition, at 2 h after injection, TNFalpha, IL-1beta converting enzyme (ICE), and IL-1 receptor antagonist (IL-1RA) mRNAs were induced in both anterior and posterior lobes. Type 1 IL-1 receptor (IL-1R1) mRNA was constitutively expressed in the pituitary, and its expression level did not change after the LPS injection. Interestingly, the mRNA coding for glial fibrillary acidic protein (GFAP), an astrocyte marker, was selectively induced in the posterior lobe at 2 h after LPS injection, suggesting that LPS affects pituicyte function. Together, these results suggest that LPS acts directly on the pituitary to rapidly induce cytokine expression. Locally synthesized cytokines may activate cytokine receptor bearing cells to modulate the endocrine activities of the pituitary.
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Affiliation(s)
- M B Whiteside
- Section on Functional Neuroanatomy, National Institute of Mental Health, Bethesda 20892-4070, USA
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43
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Murray‐Mcintosh RP. Role of Pulsatility in Hormonal Action. Compr Physiol 1998. [DOI: 10.1002/cphy.cp070119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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44
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Battaglia DF, Brown ME, Krasa HB, Thrun LA, Viguié C, Karsch FJ. Systemic challenge with endotoxin stimulates corticotropin-releasing hormone and arginine vasopressin secretion into hypophyseal portal blood: coincidence with gonadotropin-releasing hormone suppression. Endocrinology 1998; 139:4175-81. [PMID: 9751497 DOI: 10.1210/endo.139.10.6226] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We tested the hypothesis that systemic immune/inflammatory challenge (endotoxin) activates the neuroendocrine stress axis centrally by stimulating the secretion of CRH and arginine vasopressin (AVP) into hypophyseal portal blood. In addition, we examined the temporal association between this stimulation of the stress neuropeptides and the inhibition of pulsatile GnRH and LH secretion. Using alert, normally behaving ewes, hypophyseal portal and peripheral blood were sampled simultaneously at 10-min intervals for 14 h. Temperature was monitored remotely by telemetry at the same interval. Endotoxin (400 ng/kg, i.v. bolus) or saline as a control was injected after a 4-h baseline period. Portal blood was assayed for CRH, AVP, and GnRH, and peripheral blood was assayed for cortisol, progesterone, and LH. In controls, hypophyseal portal CRH and AVP remained just above or at assay sensitivity, and cortisol showed a regular rhythmic pattern unaffected by saline and typical of basal secretion. In contrast, endotoxin potently stimulated CRH and AVP secretion into portal blood, and cortisol and progesterone into peripheral blood. Both CRH and AVP generally rose and fell simultaneously, although the peak of the AVP response was approximately 10-fold greater than that of CRH. The AVP in portal blood was not due to recirculation of hormone secreted into the peripheral circulation by the posterior pituitary gland, because the AVP increase in peripheral blood was negligible relative to the marked increase in portal blood. The stimulation of CRH and AVP coincided with significant suppression of GnRH and LH pulsatile secretion in these same ewes and with the generation of fever. We conclude that endotoxin induces central activation of the neuroendocrine stress axis, stimulating both CRH and AVP release into the hypophyseal portal blood of conscious, normally behaving ewes. This response is temporally coupled to inhibition of pulsatile GnRH and LH release as well as with stimulation of adrenal cortisol and progesterone secretion and generation of fever.
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Affiliation(s)
- D F Battaglia
- Department of Physiology, University of Michigan, Ann Arbor 48109-0404, USA
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45
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YOO MJ, NISHIHARA M, TAKAHASHI M. Involvement of Prostaglandins in Suppression of Gonadotropin-Releasing Hormone Pulse Generator Activity by Tumor Necrosis Factor-.ALPHA.. J Reprod Dev 1997. [DOI: 10.1262/jrd.43.181] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Mi-Jeong YOO
- Department of Veterinary Physiology, Veterinary Medical Science, The University of Tokyo, Tokyo 113, Japan
| | - Masugi NISHIHARA
- Department of Veterinary Physiology, Veterinary Medical Science, The University of Tokyo, Tokyo 113, Japan
| | - Michio TAKAHASHI
- Department of Veterinary Physiology, Veterinary Medical Science, The University of Tokyo, Tokyo 113, Japan
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